test_strings.py

# -*- coding: utf-8 -*-
# pylint: disable-msg=E1101,W0612

from datetime import datetime, timedelta
import pytest
import re

from numpy import nan as NA
import numpy as np
from numpy.random import randint

from pandas.compat import range, u
import pandas.compat as compat
from pandas import Index, Series, DataFrame, isna, MultiIndex, notna, concat

from pandas.util.testing import assert_series_equal, assert_index_equal
import pandas.util.testing as tm

import pandas.core.strings as strings


def assert_series_or_index_equal(left, right):
    if isinstance(left, Series):
        assert_series_equal(left, right)
    else:  # Index
        assert_index_equal(left, right)


class TestStringMethods(object):

    def test_api(self):

        # GH 6106, GH 9322
        assert Series.str is strings.StringMethods
        assert isinstance(Series(['']).str, strings.StringMethods)

        # GH 9184
        invalid = Series([1])
        with pytest.raises(AttributeError, match="only use .str accessor"):
            invalid.str
        assert not hasattr(invalid, 'str')

    def test_iter(self):
        # GH3638
        strs = 'google', 'wikimedia', 'wikipedia', 'wikitravel'
        ds = Series(strs)

        for s in ds.str:
            # iter must yield a Series
            assert isinstance(s, Series)

            # indices of each yielded Series should be equal to the index of
            # the original Series
            tm.assert_index_equal(s.index, ds.index)

            for el in s:
                # each element of the series is either a basestring/str or nan
                assert isinstance(el, compat.string_types) or isna(el)

        # desired behavior is to iterate until everything would be nan on the
        # next iter so make sure the last element of the iterator was 'l' in
        # this case since 'wikitravel' is the longest string
        assert s.dropna().values.item() == 'l'

    def test_iter_empty(self):
        ds = Series([], dtype=object)

        i, s = 100, 1

        for i, s in enumerate(ds.str):
            pass

        # nothing to iterate over so nothing defined values should remain
        # unchanged
        assert i == 100
        assert s == 1

    def test_iter_single_element(self):
        ds = Series(['a'])

        for i, s in enumerate(ds.str):
            pass

        assert not i
        assert_series_equal(ds, s)

    def test_iter_object_try_string(self):
        ds = Series([slice(None, randint(10), randint(10, 20)) for _ in range(
            4)])

        i, s = 100, 'h'

        for i, s in enumerate(ds.str):
            pass

        assert i == 100
        assert s == 'h'

    @pytest.mark.parametrize('box', [Series, Index])
    @pytest.mark.parametrize('other', [None, Series, Index])
    def test_str_cat_name(self, box, other):
        # GH 21053
        values = ['a', 'b']
        if other:
            other = other(values)
        else:
            other = values
        result = box(values, name='name').str.cat(other, sep=',', join='left')
        assert result.name == 'name'

    @pytest.mark.parametrize('box', [Series, Index])
    def test_str_cat(self, box):
        # test_cat above tests "str_cat" from ndarray;
        # here testing "str.cat" from Series/Indext to ndarray/list
        s = box(['a', 'a', 'b', 'b', 'c', np.nan])

        # single array
        result = s.str.cat()
        expected = 'aabbc'
        assert result == expected

        result = s.str.cat(na_rep='-')
        expected = 'aabbc-'
        assert result == expected

        result = s.str.cat(sep='_', na_rep='NA')
        expected = 'a_a_b_b_c_NA'
        assert result == expected

        t = np.array(['a', np.nan, 'b', 'd', 'foo', np.nan], dtype=object)
        expected = box(['aa', 'a-', 'bb', 'bd', 'cfoo', '--'])

        # Series/Index with array
        result = s.str.cat(t, na_rep='-')
        assert_series_or_index_equal(result, expected)

        # Series/Index with list
        result = s.str.cat(list(t), na_rep='-')
        assert_series_or_index_equal(result, expected)

        # errors for incorrect lengths
        rgx = 'All arrays must be same length, except those having an index.*'
        z = Series(['1', '2', '3'])

        with pytest.raises(ValueError, match=rgx):
            s.str.cat(z)

        with pytest.raises(ValueError, match=rgx):
            s.str.cat(z.values)

        with pytest.raises(ValueError, match=rgx):
            s.str.cat(list(z))

    @pytest.mark.parametrize('box', [Series, Index])
    def test_str_cat_raises_intuitive_error(self, box):
        # GH 11334
        s = box(['a', 'b', 'c', 'd'])
        message = "Did you mean to supply a `sep` keyword?"
        with pytest.raises(ValueError, match=message):
            s.str.cat('|')
        with pytest.raises(ValueError, match=message):
            s.str.cat('    ')

    @pytest.mark.parametrize('sep', ['', None])
    @pytest.mark.parametrize('dtype_target', ['object', 'category'])
    @pytest.mark.parametrize('dtype_caller', ['object', 'category'])
    @pytest.mark.parametrize('box', [Series, Index])
    def test_str_cat_categorical(self, box, dtype_caller, dtype_target, sep):
        s = Index(['a', 'a', 'b', 'a'], dtype=dtype_caller)
        s = s if box == Index else Series(s, index=s)
        t = Index(['b', 'a', 'b', 'c'], dtype=dtype_target)

        expected = Index(['ab', 'aa', 'bb', 'ac'])
        expected = expected if box == Index else Series(expected, index=s)

        # Series/Index with unaligned Index
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # FutureWarning to switch to alignment by default
            result = s.str.cat(t, sep=sep)
            assert_series_or_index_equal(result, expected)

        # Series/Index with Series having matching Index
        t = Series(t, index=s)
        result = s.str.cat(t, sep=sep)
        assert_series_or_index_equal(result, expected)

        # Series/Index with Series.values
        result = s.str.cat(t.values, sep=sep)
        assert_series_or_index_equal(result, expected)

        # Series/Index with Series having different Index
        t = Series(t.values, index=t)
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # FutureWarning to switch to alignment by default
            result = s.str.cat(t, sep=sep)
            assert_series_or_index_equal(result, expected)

    @pytest.mark.parametrize('box', [Series, Index])
    def test_str_cat_mixed_inputs(self, box):
        s = Index(['a', 'b', 'c', 'd'])
        s = s if box == Index else Series(s, index=s)

        t = Series(['A', 'B', 'C', 'D'], index=s.values)
        d = concat([t, Series(s, index=s)], axis=1)

        expected = Index(['aAa', 'bBb', 'cCc', 'dDd'])
        expected = expected if box == Index else Series(expected.values,
                                                        index=s.values)

        # Series/Index with DataFrame
        result = s.str.cat(d)
        assert_series_or_index_equal(result, expected)

        # Series/Index with two-dimensional ndarray
        result = s.str.cat(d.values)
        assert_series_or_index_equal(result, expected)

        # Series/Index with list of Series
        result = s.str.cat([t, s])
        assert_series_or_index_equal(result, expected)

        # Series/Index with mixed list of Series/array
        result = s.str.cat([t, s.values])
        assert_series_or_index_equal(result, expected)

        # Series/Index with list of list-likes
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # nested list-likes will be deprecated
            result = s.str.cat([t.values, list(s)])
            assert_series_or_index_equal(result, expected)

        # Series/Index with list of Series; different indexes
        t.index = ['b', 'c', 'd', 'a']
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # FutureWarning to switch to alignment by default
            result = s.str.cat([t, s])
            assert_series_or_index_equal(result, expected)

        # Series/Index with mixed list; different indexes
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # FutureWarning to switch to alignment by default
            result = s.str.cat([t, s.values])
            assert_series_or_index_equal(result, expected)

        # Series/Index with DataFrame; different indexes
        d.index = ['b', 'c', 'd', 'a']
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # FutureWarning to switch to alignment by default
            result = s.str.cat(d)
            assert_series_or_index_equal(result, expected)

        # Series/Index with iterator of list-likes
        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # nested list-likes will be deprecated
            result = s.str.cat(iter([t.values, list(s)]))
            assert_series_or_index_equal(result, expected)

        # errors for incorrect lengths
        rgx = 'All arrays must be same length, except those having an index.*'
        z = Series(['1', '2', '3'])
        e = concat([z, z], axis=1)

        # DataFrame
        with pytest.raises(ValueError, match=rgx):
            s.str.cat(e)

        # two-dimensional ndarray
        with pytest.raises(ValueError, match=rgx):
            s.str.cat(e.values)

        # list of Series
        with pytest.raises(ValueError, match=rgx):
            s.str.cat([z, s])

        # list of list-likes
        with pytest.raises(ValueError, match=rgx):
            s.str.cat([z.values, s.values])

        # mixed list of Series/list-like
        with pytest.raises(ValueError, match=rgx):
            s.str.cat([z.values, s])

        # errors for incorrect arguments in list-like
        rgx = 'others must be Series, Index, DataFrame,.*'
        # make sure None/NaN do not crash checks in _get_series_list
        u = Series(['a', np.nan, 'c', None])

        # mix of string and Series
        with pytest.raises(TypeError, match=rgx):
            s.str.cat([u, 'u'])

        # DataFrame in list
        with pytest.raises(TypeError, match=rgx):
            s.str.cat([u, d])

        # 2-dim ndarray in list
        with pytest.raises(TypeError, match=rgx):
            s.str.cat([u, d.values])

        # nested lists
        with pytest.raises(TypeError, match=rgx):
            s.str.cat([u, [u, d]])

        # forbidden input type: set
        # GH 23009
        with pytest.raises(TypeError, match=rgx):
            s.str.cat(set(u))

        # forbidden input type: set in list
        # GH 23009
        with pytest.raises(TypeError, match=rgx):
            s.str.cat([u, set(u)])

        # other forbidden input type, e.g. int
        with pytest.raises(TypeError, match=rgx):
            s.str.cat(1)

    @pytest.mark.parametrize('join', ['left', 'outer', 'inner', 'right'])
    @pytest.mark.parametrize('box', [Series, Index])
    def test_str_cat_align_indexed(self, box, join):
        # https://github.com/pandas-dev/pandas/issues/18657
        s = Series(['a', 'b', 'c', 'd'], index=['a', 'b', 'c', 'd'])
        t = Series(['D', 'A', 'E', 'B'], index=['d', 'a', 'e', 'b'])
        sa, ta = s.align(t, join=join)
        # result after manual alignment of inputs
        expected = sa.str.cat(ta, na_rep='-')

        if box == Index:
            s = Index(s)
            sa = Index(sa)
            expected = Index(expected)

        result = s.str.cat(t, join=join, na_rep='-')
        assert_series_or_index_equal(result, expected)

    @pytest.mark.parametrize('join', ['left', 'outer', 'inner', 'right'])
    def test_str_cat_align_mixed_inputs(self, join):
        s = Series(['a', 'b', 'c', 'd'])
        t = Series(['d', 'a', 'e', 'b'], index=[3, 0, 4, 1])
        d = concat([t, t], axis=1)

        expected_outer = Series(['aaa', 'bbb', 'c--', 'ddd', '-ee'])
        expected = expected_outer.loc[s.index.join(t.index, how=join)]

        # list of Series
        result = s.str.cat([t, t], join=join, na_rep='-')
        tm.assert_series_equal(result, expected)

        # DataFrame
        result = s.str.cat(d, join=join, na_rep='-')
        tm.assert_series_equal(result, expected)

        # mixed list of indexed/unindexed
        u = np.array(['A', 'B', 'C', 'D'])
        expected_outer = Series(['aaA', 'bbB', 'c-C', 'ddD', '-e-'])
        # joint index of rhs [t, u]; u will be forced have index of s
        rhs_idx = t.index & s.index if join == 'inner' else t.index | s.index

        expected = expected_outer.loc[s.index.join(rhs_idx, how=join)]
        result = s.str.cat([t, u], join=join, na_rep='-')
        tm.assert_series_equal(result, expected)

        with tm.assert_produces_warning(expected_warning=FutureWarning):
            # nested list-likes will be deprecated
            result = s.str.cat([t, list(u)], join=join, na_rep='-')
            tm.assert_series_equal(result, expected)

        # errors for incorrect lengths
        rgx = r'If `others` contains arrays or lists \(or other list-likes.*'
        z = Series(['1', '2', '3']).values

        # unindexed object of wrong length
        with pytest.raises(ValueError, match=rgx):
            s.str.cat(z, join=join)

        # unindexed object of wrong length in list
        with pytest.raises(ValueError, match=rgx):
            s.str.cat([t, z], join=join)

    def test_str_cat_raises(self):
        # non-strings hiding behind object dtype
        s = Series([1, 2, 3, 4], dtype='object')
        with pytest.raises(TypeError, match="unsupported operand type.*"):
            s.str.cat(s)

    def test_str_cat_special_cases(self):
        s = Series(['a', 'b', 'c', 'd'])
        t = Series(['d', 'a', 'e', 'b'], index=[3, 0, 4, 1])

        # iterator of elements with different types
        expected = Series(['aaa', 'bbb', 'c-c', 'ddd', '-e-'])
        result = s.str.cat(iter([t, s.values]), join='outer', na_rep='-')
        tm.assert_series_equal(result, expected)

        # right-align with different indexes in others
        expected = Series(['aa-', 'd-d'], index=[0, 3])
        result = s.str.cat([t.loc[[0]], t.loc[[3]]], join='right', na_rep='-')
        tm.assert_series_equal(result, expected)

    def test_cat_on_filtered_index(self):
        df = DataFrame(index=MultiIndex.from_product(
            [[2011, 2012], [1, 2, 3]], names=['year', 'month']))

        df = df.reset_index()
        df = df[df.month > 1]

        str_year = df.year.astype('str')
        str_month = df.month.astype('str')
        str_both = str_year.str.cat(str_month, sep=' ')

        assert str_both.loc[1] == '2011 2'

        str_multiple = str_year.str.cat([str_month, str_month], sep=' ')

        assert str_multiple.loc[1] == '2011 2 2'

    def test_count(self):
        values = np.array(['foo', 'foofoo', NA, 'foooofooofommmfoo'],
                          dtype=np.object_)

        result = strings.str_count(values, 'f[o]+')
        exp = np.array([1, 2, NA, 4])
        tm.assert_numpy_array_equal(result, exp)

        result = Series(values).str.count('f[o]+')
        exp = Series([1, 2, NA, 4])
        assert isinstance(result, Series)
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = ['a', NA, 'b', True, datetime.today(), 'foo', None, 1, 2.]
        rs = strings.str_count(mixed, 'a')
        xp = np.array([1, NA, 0, NA, NA, 0, NA, NA, NA])
        tm.assert_numpy_array_equal(rs, xp)

        rs = Series(mixed).str.count('a')
        xp = Series([1, NA, 0, NA, NA, 0, NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = [u('foo'), u('foofoo'), NA, u('foooofooofommmfoo')]

        result = strings.str_count(values, 'f[o]+')
        exp = np.array([1, 2, NA, 4])
        tm.assert_numpy_array_equal(result, exp)

        result = Series(values).str.count('f[o]+')
        exp = Series([1, 2, NA, 4])
        assert isinstance(result, Series)
        tm.assert_series_equal(result, exp)

    def test_contains(self):
        values = np.array(['foo', NA, 'fooommm__foo',
                           'mmm_', 'foommm[_]+bar'], dtype=np.object_)
        pat = 'mmm[_]+'

        result = strings.str_contains(values, pat)
        expected = np.array([False, NA, True, True, False], dtype=np.object_)
        tm.assert_numpy_array_equal(result, expected)

        result = strings.str_contains(values, pat, regex=False)
        expected = np.array([False, NA, False, False, True], dtype=np.object_)
        tm.assert_numpy_array_equal(result, expected)

        values = ['foo', 'xyz', 'fooommm__foo', 'mmm_']
        result = strings.str_contains(values, pat)
        expected = np.array([False, False, True, True])
        assert result.dtype == np.bool_
        tm.assert_numpy_array_equal(result, expected)

        # case insensitive using regex
        values = ['Foo', 'xYz', 'fOOomMm__fOo', 'MMM_']
        result = strings.str_contains(values, 'FOO|mmm', case=False)
        expected = np.array([True, False, True, True])
        tm.assert_numpy_array_equal(result, expected)

        # case insensitive without regex
        result = strings.str_contains(values, 'foo', regex=False, case=False)
        expected = np.array([True, False, True, False])
        tm.assert_numpy_array_equal(result, expected)

        # mixed
        mixed = ['a', NA, 'b', True, datetime.today(), 'foo', None, 1, 2.]
        rs = strings.str_contains(mixed, 'o')
        xp = np.array([False, NA, False, NA, NA, True, NA, NA, NA],
                      dtype=np.object_)
        tm.assert_numpy_array_equal(rs, xp)

        rs = Series(mixed).str.contains('o')
        xp = Series([False, NA, False, NA, NA, True, NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = np.array([u'foo', NA, u'fooommm__foo', u'mmm_'],
                          dtype=np.object_)
        pat = 'mmm[_]+'

        result = strings.str_contains(values, pat)
        expected = np.array([False, np.nan, True, True], dtype=np.object_)
        tm.assert_numpy_array_equal(result, expected)

        result = strings.str_contains(values, pat, na=False)
        expected = np.array([False, False, True, True])
        tm.assert_numpy_array_equal(result, expected)

        values = np.array(['foo', 'xyz', 'fooommm__foo', 'mmm_'],
                          dtype=np.object_)
        result = strings.str_contains(values, pat)
        expected = np.array([False, False, True, True])
        assert result.dtype == np.bool_
        tm.assert_numpy_array_equal(result, expected)

        # na
        values = Series(['om', 'foo', np.nan])
        res = values.str.contains('foo', na="foo")
        assert res.loc[2] == "foo"

    def test_startswith(self):
        values = Series(['om', NA, 'foo_nom', 'nom', 'bar_foo', NA, 'foo'])

        result = values.str.startswith('foo')
        exp = Series([False, NA, True, False, False, NA, True])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = np.array(['a', NA, 'b', True, datetime.today(),
                          'foo', None, 1, 2.], dtype=np.object_)
        rs = strings.str_startswith(mixed, 'f')
        xp = np.array([False, NA, False, NA, NA, True, NA, NA, NA],
                      dtype=np.object_)
        tm.assert_numpy_array_equal(rs, xp)

        rs = Series(mixed).str.startswith('f')
        assert isinstance(rs, Series)
        xp = Series([False, NA, False, NA, NA, True, NA, NA, NA])
        tm.assert_series_equal(rs, xp)

        # unicode
        values = Series([u('om'), NA, u('foo_nom'), u('nom'), u('bar_foo'), NA,
                         u('foo')])

        result = values.str.startswith('foo')
        exp = Series([False, NA, True, False, False, NA, True])
        tm.assert_series_equal(result, exp)

        result = values.str.startswith('foo', na=True)
        tm.assert_series_equal(result, exp.fillna(True).astype(bool))

    def test_endswith(self):
        values = Series(['om', NA, 'foo_nom', 'nom', 'bar_foo', NA, 'foo'])

        result = values.str.endswith('foo')
        exp = Series([False, NA, False, False, True, NA, True])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = ['a', NA, 'b', True, datetime.today(), 'foo', None, 1, 2.]
        rs = strings.str_endswith(mixed, 'f')
        xp = np.array([False, NA, False, NA, NA, False, NA, NA, NA],
                      dtype=np.object_)
        tm.assert_numpy_array_equal(rs, xp)

        rs = Series(mixed).str.endswith('f')
        xp = Series([False, NA, False, NA, NA, False, NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = Series([u('om'), NA, u('foo_nom'), u('nom'), u('bar_foo'), NA,
                         u('foo')])

        result = values.str.endswith('foo')
        exp = Series([False, NA, False, False, True, NA, True])
        tm.assert_series_equal(result, exp)

        result = values.str.endswith('foo', na=False)
        tm.assert_series_equal(result, exp.fillna(False).astype(bool))

    def test_title(self):
        values = Series(["FOO", "BAR", NA, "Blah", "blurg"])

        result = values.str.title()
        exp = Series(["Foo", "Bar", NA, "Blah", "Blurg"])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(["FOO", NA, "bar", True, datetime.today(), "blah", None,
                        1, 2.])
        mixed = mixed.str.title()
        exp = Series(["Foo", NA, "Bar", NA, NA, "Blah", NA, NA, NA])
        tm.assert_almost_equal(mixed, exp)

        # unicode
        values = Series([u("FOO"), NA, u("bar"), u("Blurg")])

        results = values.str.title()
        exp = Series([u("Foo"), NA, u("Bar"), u("Blurg")])

        tm.assert_series_equal(results, exp)

    def test_lower_upper(self):
        values = Series(['om', NA, 'nom', 'nom'])

        result = values.str.upper()
        exp = Series(['OM', NA, 'NOM', 'NOM'])
        tm.assert_series_equal(result, exp)

        result = result.str.lower()
        tm.assert_series_equal(result, values)

        # mixed
        mixed = Series(['a', NA, 'b', True, datetime.today(), 'foo', None, 1,
                        2.])
        mixed = mixed.str.upper()
        rs = Series(mixed).str.lower()
        xp = Series(['a', NA, 'b', NA, NA, 'foo', NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = Series([u('om'), NA, u('nom'), u('nom')])

        result = values.str.upper()
        exp = Series([u('OM'), NA, u('NOM'), u('NOM')])
        tm.assert_series_equal(result, exp)

        result = result.str.lower()
        tm.assert_series_equal(result, values)

    def test_capitalize(self):
        values = Series(["FOO", "BAR", NA, "Blah", "blurg"])
        result = values.str.capitalize()
        exp = Series(["Foo", "Bar", NA, "Blah", "Blurg"])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(["FOO", NA, "bar", True, datetime.today(), "blah", None,
                        1, 2.])
        mixed = mixed.str.capitalize()
        exp = Series(["Foo", NA, "Bar", NA, NA, "Blah", NA, NA, NA])
        tm.assert_almost_equal(mixed, exp)

        # unicode
        values = Series([u("FOO"), NA, u("bar"), u("Blurg")])
        results = values.str.capitalize()
        exp = Series([u("Foo"), NA, u("Bar"), u("Blurg")])
        tm.assert_series_equal(results, exp)

    def test_swapcase(self):
        values = Series(["FOO", "BAR", NA, "Blah", "blurg"])
        result = values.str.swapcase()
        exp = Series(["foo", "bar", NA, "bLAH", "BLURG"])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(["FOO", NA, "bar", True, datetime.today(), "Blah", None,
                        1, 2.])
        mixed = mixed.str.swapcase()
        exp = Series(["foo", NA, "BAR", NA, NA, "bLAH", NA, NA, NA])
        tm.assert_almost_equal(mixed, exp)

        # unicode
        values = Series([u("FOO"), NA, u("bar"), u("Blurg")])
        results = values.str.swapcase()
        exp = Series([u("foo"), NA, u("BAR"), u("bLURG")])
        tm.assert_series_equal(results, exp)

    def test_casemethods(self):
        values = ['aaa', 'bbb', 'CCC', 'Dddd', 'eEEE']
        s = Series(values)
        assert s.str.lower().tolist() == [v.lower() for v in values]
        assert s.str.upper().tolist() == [v.upper() for v in values]
        assert s.str.title().tolist() == [v.title() for v in values]
        assert s.str.capitalize().tolist() == [v.capitalize() for v in values]
        assert s.str.swapcase().tolist() == [v.swapcase() for v in values]

    def test_replace(self):
        values = Series(['fooBAD__barBAD', NA])

        result = values.str.replace('BAD[_]*', '')
        exp = Series(['foobar', NA])
        tm.assert_series_equal(result, exp)

        result = values.str.replace('BAD[_]*', '', n=1)
        exp = Series(['foobarBAD', NA])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['aBAD', NA, 'bBAD', True, datetime.today(), 'fooBAD',
                        None, 1, 2.])

        rs = Series(mixed).str.replace('BAD[_]*', '')
        xp = Series(['a', NA, 'b', NA, NA, 'foo', NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA])

        result = values.str.replace('BAD[_]*', '')
        exp = Series([u('foobar'), NA])
        tm.assert_series_equal(result, exp)

        result = values.str.replace('BAD[_]*', '', n=1)
        exp = Series([u('foobarBAD'), NA])
        tm.assert_series_equal(result, exp)

        # flags + unicode
        values = Series([b"abcd,\xc3\xa0".decode("utf-8")])
        exp = Series([b"abcd, \xc3\xa0".decode("utf-8")])
        result = values.str.replace(r"(?<=\w),(?=\w)", ", ", flags=re.UNICODE)
        tm.assert_series_equal(result, exp)

        # GH 13438
        for klass in (Series, Index):
            for repl in (None, 3, {'a': 'b'}):
                for data in (['a', 'b', None], ['a', 'b', 'c', 'ad']):
                    values = klass(data)
                    pytest.raises(TypeError, values.str.replace, 'a', repl)

    def test_replace_callable(self):
        # GH 15055
        values = Series(['fooBAD__barBAD', NA])

        # test with callable
        repl = lambda m: m.group(0).swapcase()
        result = values.str.replace('[a-z][A-Z]{2}', repl, n=2)
        exp = Series(['foObaD__baRbaD', NA])
        tm.assert_series_equal(result, exp)

        # test with wrong number of arguments, raising an error
        if compat.PY2:
            p_err = r'takes (no|(exactly|at (least|most)) ?\d+) arguments?'
        else:
            p_err = (r'((takes)|(missing)) (?(2)from \d+ to )?\d+ '
                     r'(?(3)required )positional arguments?')

        repl = lambda: None
        with pytest.raises(TypeError, match=p_err):
            values.str.replace('a', repl)

        repl = lambda m, x: None
        with pytest.raises(TypeError, match=p_err):
            values.str.replace('a', repl)

        repl = lambda m, x, y=None: None
        with pytest.raises(TypeError, match=p_err):
            values.str.replace('a', repl)

        # test regex named groups
        values = Series(['Foo Bar Baz', NA])
        pat = r"(?P<first>\w+) (?P<middle>\w+) (?P<last>\w+)"
        repl = lambda m: m.group('middle').swapcase()
        result = values.str.replace(pat, repl)
        exp = Series(['bAR', NA])
        tm.assert_series_equal(result, exp)

    def test_replace_compiled_regex(self):
        # GH 15446
        values = Series(['fooBAD__barBAD', NA])

        # test with compiled regex
        pat = re.compile(r'BAD[_]*')
        result = values.str.replace(pat, '')
        exp = Series(['foobar', NA])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['aBAD', NA, 'bBAD', True, datetime.today(), 'fooBAD',
                        None, 1, 2.])

        rs = Series(mixed).str.replace(pat, '')
        xp = Series(['a', NA, 'b', NA, NA, 'foo', NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA])

        result = values.str.replace(pat, '')
        exp = Series([u('foobar'), NA])
        tm.assert_series_equal(result, exp)

        result = values.str.replace(pat, '', n=1)
        exp = Series([u('foobarBAD'), NA])
        tm.assert_series_equal(result, exp)

        # flags + unicode
        values = Series([b"abcd,\xc3\xa0".decode("utf-8")])
        exp = Series([b"abcd, \xc3\xa0".decode("utf-8")])
        pat = re.compile(r"(?<=\w),(?=\w)", flags=re.UNICODE)
        result = values.str.replace(pat, ", ")
        tm.assert_series_equal(result, exp)

        # case and flags provided to str.replace will have no effect
        # and will produce warnings
        values = Series(['fooBAD__barBAD__bad', NA])
        pat = re.compile(r'BAD[_]*')

        with pytest.raises(ValueError,
                           match="case and flags cannot be"):
            result = values.str.replace(pat, '', flags=re.IGNORECASE)

        with pytest.raises(ValueError,
                           match="case and flags cannot be"):
            result = values.str.replace(pat, '', case=False)

        with pytest.raises(ValueError,
                           match="case and flags cannot be"):
            result = values.str.replace(pat, '', case=True)

        # test with callable
        values = Series(['fooBAD__barBAD', NA])
        repl = lambda m: m.group(0).swapcase()
        pat = re.compile('[a-z][A-Z]{2}')
        result = values.str.replace(pat, repl, n=2)
        exp = Series(['foObaD__baRbaD', NA])
        tm.assert_series_equal(result, exp)

    def test_replace_literal(self):
        # GH16808 literal replace (regex=False vs regex=True)
        values = Series(['f.o', 'foo', NA])
        exp = Series(['bao', 'bao', NA])
        result = values.str.replace('f.', 'ba')
        tm.assert_series_equal(result, exp)

        exp = Series(['bao', 'foo', NA])
        result = values.str.replace('f.', 'ba', regex=False)
        tm.assert_series_equal(result, exp)

        # Cannot do a literal replace if given a callable repl or compiled
        # pattern
        callable_repl = lambda m: m.group(0).swapcase()
        compiled_pat = re.compile('[a-z][A-Z]{2}')

        pytest.raises(ValueError, values.str.replace, 'abc', callable_repl,
                      regex=False)
        pytest.raises(ValueError, values.str.replace, compiled_pat, '',
                      regex=False)

    def test_repeat(self):
        values = Series(['a', 'b', NA, 'c', NA, 'd'])

        result = values.str.repeat(3)
        exp = Series(['aaa', 'bbb', NA, 'ccc', NA, 'ddd'])
        tm.assert_series_equal(result, exp)

        result = values.str.repeat([1, 2, 3, 4, 5, 6])
        exp = Series(['a', 'bb', NA, 'cccc', NA, 'dddddd'])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['a', NA, 'b', True, datetime.today(), 'foo', None, 1,
                        2.])

        rs = Series(mixed).str.repeat(3)
        xp = Series(['aaa', NA, 'bbb', NA, NA, 'foofoofoo', NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = Series([u('a'), u('b'), NA, u('c'), NA, u('d')])

        result = values.str.repeat(3)
        exp = Series([u('aaa'), u('bbb'), NA, u('ccc'), NA, u('ddd')])
        tm.assert_series_equal(result, exp)

        result = values.str.repeat([1, 2, 3, 4, 5, 6])
        exp = Series([u('a'), u('bb'), NA, u('cccc'), NA, u('dddddd')])
        tm.assert_series_equal(result, exp)

    def test_match(self):
        # New match behavior introduced in 0.13
        values = Series(['fooBAD__barBAD', NA, 'foo'])
        result = values.str.match('.*(BAD[_]+).*(BAD)')
        exp = Series([True, NA, False])
        tm.assert_series_equal(result, exp)

        values = Series(['fooBAD__barBAD', NA, 'foo'])
        result = values.str.match('.*BAD[_]+.*BAD')
        exp = Series([True, NA, False])
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['aBAD_BAD', NA, 'BAD_b_BAD', True, datetime.today(),
                        'foo', None, 1, 2.])
        rs = Series(mixed).str.match('.*(BAD[_]+).*(BAD)')
        xp = Series([True, NA, True, NA, NA, False, NA, NA, NA])
        assert isinstance(rs, Series)
        tm.assert_series_equal(rs, xp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA, u('foo')])
        result = values.str.match('.*(BAD[_]+).*(BAD)')
        exp = Series([True, NA, False])
        tm.assert_series_equal(result, exp)

        # na GH #6609
        res = Series(['a', 0, np.nan]).str.match('a', na=False)
        exp = Series([True, False, False])
        assert_series_equal(exp, res)
        res = Series(['a', 0, np.nan]).str.match('a')
        exp = Series([True, np.nan, np.nan])
        assert_series_equal(exp, res)

    def test_extract_expand_None(self):
        values = Series(['fooBAD__barBAD', NA, 'foo'])
        with pytest.raises(ValueError,
                           match='expand must be True or False'):
            values.str.extract('.*(BAD[_]+).*(BAD)', expand=None)

    def test_extract_expand_unspecified(self):
        values = Series(['fooBAD__barBAD', NA, 'foo'])
        result_unspecified = values.str.extract('.*(BAD[_]+).*')
        assert isinstance(result_unspecified, DataFrame)
        result_true = values.str.extract('.*(BAD[_]+).*', expand=True)
        tm.assert_frame_equal(result_unspecified, result_true)

    def test_extract_expand_False(self):
        # Contains tests like those in test_match and some others.
        values = Series(['fooBAD__barBAD', NA, 'foo'])
        er = [NA, NA]  # empty row

        result = values.str.extract('.*(BAD[_]+).*(BAD)', expand=False)
        exp = DataFrame([['BAD__', 'BAD'], er, er])
        tm.assert_frame_equal(result, exp)

        # mixed
        mixed = Series(['aBAD_BAD', NA, 'BAD_b_BAD', True, datetime.today(),
                        'foo', None, 1, 2.])

        rs = Series(mixed).str.extract('.*(BAD[_]+).*(BAD)', expand=False)
        exp = DataFrame([['BAD_', 'BAD'], er, ['BAD_', 'BAD'], er, er, er, er,
                         er, er])
        tm.assert_frame_equal(rs, exp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA, u('foo')])

        result = values.str.extract('.*(BAD[_]+).*(BAD)', expand=False)
        exp = DataFrame([[u('BAD__'), u('BAD')], er, er])
        tm.assert_frame_equal(result, exp)

        # GH9980
        # Index only works with one regex group since
        # multi-group would expand to a frame
        idx = Index(['A1', 'A2', 'A3', 'A4', 'B5'])
        with pytest.raises(ValueError, match="supported"):
            idx.str.extract('([AB])([123])', expand=False)

        # these should work for both Series and Index
        for klass in [Series, Index]:
            # no groups
            s_or_idx = klass(['A1', 'B2', 'C3'])
            f = lambda: s_or_idx.str.extract('[ABC][123]', expand=False)
            pytest.raises(ValueError, f)

            # only non-capturing groups
            f = lambda: s_or_idx.str.extract('(?:[AB]).*', expand=False)
            pytest.raises(ValueError, f)

            # single group renames series/index properly
            s_or_idx = klass(['A1', 'A2'])
            result = s_or_idx.str.extract(r'(?P<uno>A)\d', expand=False)
            assert result.name == 'uno'

            exp = klass(['A', 'A'], name='uno')
            if klass == Series:
                tm.assert_series_equal(result, exp)
            else:
                tm.assert_index_equal(result, exp)

        s = Series(['A1', 'B2', 'C3'])
        # one group, no matches
        result = s.str.extract('(_)', expand=False)
        exp = Series([NA, NA, NA], dtype=object)
        tm.assert_series_equal(result, exp)

        # two groups, no matches
        result = s.str.extract('(_)(_)', expand=False)
        exp = DataFrame([[NA, NA], [NA, NA], [NA, NA]], dtype=object)
        tm.assert_frame_equal(result, exp)

        # one group, some matches
        result = s.str.extract('([AB])[123]', expand=False)
        exp = Series(['A', 'B', NA])
        tm.assert_series_equal(result, exp)

        # two groups, some matches
        result = s.str.extract('([AB])([123])', expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]])
        tm.assert_frame_equal(result, exp)

        # one named group
        result = s.str.extract('(?P<letter>[AB])', expand=False)
        exp = Series(['A', 'B', NA], name='letter')
        tm.assert_series_equal(result, exp)

        # two named groups
        result = s.str.extract('(?P<letter>[AB])(?P<number>[123])',
                               expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]],
                        columns=['letter', 'number'])
        tm.assert_frame_equal(result, exp)

        # mix named and unnamed groups
        result = s.str.extract('([AB])(?P<number>[123])', expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]],
                        columns=[0, 'number'])
        tm.assert_frame_equal(result, exp)

        # one normal group, one non-capturing group
        result = s.str.extract('([AB])(?:[123])', expand=False)
        exp = Series(['A', 'B', NA])
        tm.assert_series_equal(result, exp)

        # two normal groups, one non-capturing group
        result = Series(['A11', 'B22', 'C33']).str.extract(
            '([AB])([123])(?:[123])', expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]])
        tm.assert_frame_equal(result, exp)

        # one optional group followed by one normal group
        result = Series(['A1', 'B2', '3']).str.extract(
            '(?P<letter>[AB])?(?P<number>[123])', expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, '3']],
                        columns=['letter', 'number'])
        tm.assert_frame_equal(result, exp)

        # one normal group followed by one optional group
        result = Series(['A1', 'B2', 'C']).str.extract(
            '(?P<letter>[ABC])(?P<number>[123])?', expand=False)
        exp = DataFrame([['A', '1'], ['B', '2'], ['C', NA]],
                        columns=['letter', 'number'])
        tm.assert_frame_equal(result, exp)

        # GH6348
        # not passing index to the extractor
        def check_index(index):
            data = ['A1', 'B2', 'C']
            index = index[:len(data)]
            s = Series(data, index=index)
            result = s.str.extract(r'(\d)', expand=False)
            exp = Series(['1', '2', NA], index=index)
            tm.assert_series_equal(result, exp)

            result = Series(data, index=index).str.extract(
                r'(?P<letter>\D)(?P<number>\d)?', expand=False)
            e_list = [
                ['A', '1'],
                ['B', '2'],
                ['C', NA]
            ]
            exp = DataFrame(e_list, columns=['letter', 'number'], index=index)
            tm.assert_frame_equal(result, exp)

        i_funs = [
            tm.makeStringIndex, tm.makeUnicodeIndex, tm.makeIntIndex,
            tm.makeDateIndex, tm.makePeriodIndex, tm.makeRangeIndex
        ]
        for index in i_funs:
            check_index(index())

        # single_series_name_is_preserved.
        s = Series(['a3', 'b3', 'c2'], name='bob')
        r = s.str.extract(r'(?P<sue>[a-z])', expand=False)
        e = Series(['a', 'b', 'c'], name='sue')
        tm.assert_series_equal(r, e)
        assert r.name == e.name

    def test_extract_expand_True(self):
        # Contains tests like those in test_match and some others.
        values = Series(['fooBAD__barBAD', NA, 'foo'])
        er = [NA, NA]  # empty row

        result = values.str.extract('.*(BAD[_]+).*(BAD)', expand=True)
        exp = DataFrame([['BAD__', 'BAD'], er, er])
        tm.assert_frame_equal(result, exp)

        # mixed
        mixed = Series(['aBAD_BAD', NA, 'BAD_b_BAD', True, datetime.today(),
                        'foo', None, 1, 2.])

        rs = Series(mixed).str.extract('.*(BAD[_]+).*(BAD)', expand=True)
        exp = DataFrame([['BAD_', 'BAD'], er, ['BAD_', 'BAD'], er, er,
                         er, er, er, er])
        tm.assert_frame_equal(rs, exp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA, u('foo')])

        result = values.str.extract('.*(BAD[_]+).*(BAD)', expand=True)
        exp = DataFrame([[u('BAD__'), u('BAD')], er, er])
        tm.assert_frame_equal(result, exp)

        # these should work for both Series and Index
        for klass in [Series, Index]:
            # no groups
            s_or_idx = klass(['A1', 'B2', 'C3'])
            f = lambda: s_or_idx.str.extract('[ABC][123]', expand=True)
            pytest.raises(ValueError, f)

            # only non-capturing groups
            f = lambda: s_or_idx.str.extract('(?:[AB]).*', expand=True)
            pytest.raises(ValueError, f)

            # single group renames series/index properly
            s_or_idx = klass(['A1', 'A2'])
            result_df = s_or_idx.str.extract(r'(?P<uno>A)\d', expand=True)
            assert isinstance(result_df, DataFrame)
            result_series = result_df['uno']
            assert_series_equal(result_series, Series(['A', 'A'], name='uno'))

    def test_extract_series(self):
        # extract should give the same result whether or not the
        # series has a name.
        for series_name in None, "series_name":
            s = Series(['A1', 'B2', 'C3'], name=series_name)
            # one group, no matches
            result = s.str.extract('(_)', expand=True)
            exp = DataFrame([NA, NA, NA], dtype=object)
            tm.assert_frame_equal(result, exp)

            # two groups, no matches
            result = s.str.extract('(_)(_)', expand=True)
            exp = DataFrame([[NA, NA], [NA, NA], [NA, NA]], dtype=object)
            tm.assert_frame_equal(result, exp)

            # one group, some matches
            result = s.str.extract('([AB])[123]', expand=True)
            exp = DataFrame(['A', 'B', NA])
            tm.assert_frame_equal(result, exp)

            # two groups, some matches
            result = s.str.extract('([AB])([123])', expand=True)
            exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]])
            tm.assert_frame_equal(result, exp)

            # one named group
            result = s.str.extract('(?P<letter>[AB])', expand=True)
            exp = DataFrame({"letter": ['A', 'B', NA]})
            tm.assert_frame_equal(result, exp)

            # two named groups
            result = s.str.extract(
                '(?P<letter>[AB])(?P<number>[123])',
                expand=True)
            e_list = [
                ['A', '1'],
                ['B', '2'],
                [NA, NA]
            ]
            exp = DataFrame(e_list, columns=['letter', 'number'])
            tm.assert_frame_equal(result, exp)

            # mix named and unnamed groups
            result = s.str.extract('([AB])(?P<number>[123])', expand=True)
            exp = DataFrame(e_list, columns=[0, 'number'])
            tm.assert_frame_equal(result, exp)

            # one normal group, one non-capturing group
            result = s.str.extract('([AB])(?:[123])', expand=True)
            exp = DataFrame(['A', 'B', NA])
            tm.assert_frame_equal(result, exp)

    def test_extract_optional_groups(self):

        # two normal groups, one non-capturing group
        result = Series(['A11', 'B22', 'C33']).str.extract(
            '([AB])([123])(?:[123])', expand=True)
        exp = DataFrame([['A', '1'], ['B', '2'], [NA, NA]])
        tm.assert_frame_equal(result, exp)

        # one optional group followed by one normal group
        result = Series(['A1', 'B2', '3']).str.extract(
            '(?P<letter>[AB])?(?P<number>[123])', expand=True)
        e_list = [
            ['A', '1'],
            ['B', '2'],
            [NA, '3']
        ]
        exp = DataFrame(e_list, columns=['letter', 'number'])
        tm.assert_frame_equal(result, exp)

        # one normal group followed by one optional group
        result = Series(['A1', 'B2', 'C']).str.extract(
            '(?P<letter>[ABC])(?P<number>[123])?', expand=True)
        e_list = [
            ['A', '1'],
            ['B', '2'],
            ['C', NA]
        ]
        exp = DataFrame(e_list, columns=['letter', 'number'])
        tm.assert_frame_equal(result, exp)

        # GH6348
        # not passing index to the extractor
        def check_index(index):
            data = ['A1', 'B2', 'C']
            index = index[:len(data)]
            result = Series(data, index=index).str.extract(
                r'(\d)', expand=True)
            exp = DataFrame(['1', '2', NA], index=index)
            tm.assert_frame_equal(result, exp)

            result = Series(data, index=index).str.extract(
                r'(?P<letter>\D)(?P<number>\d)?', expand=True)
            e_list = [
                ['A', '1'],
                ['B', '2'],
                ['C', NA]
            ]
            exp = DataFrame(e_list, columns=['letter', 'number'], index=index)
            tm.assert_frame_equal(result, exp)

        i_funs = [
            tm.makeStringIndex, tm.makeUnicodeIndex, tm.makeIntIndex,
            tm.makeDateIndex, tm.makePeriodIndex, tm.makeRangeIndex
        ]
        for index in i_funs:
            check_index(index())

    def test_extract_single_group_returns_frame(self):
        # GH11386 extract should always return DataFrame, even when
        # there is only one group. Prior to v0.18.0, extract returned
        # Series when there was only one group in the regex.
        s = Series(['a3', 'b3', 'c2'], name='series_name')
        r = s.str.extract(r'(?P<letter>[a-z])', expand=True)
        e = DataFrame({"letter": ['a', 'b', 'c']})
        tm.assert_frame_equal(r, e)

    def test_extractall(self):
        subject_list = [
            'dave@google.com',
            'tdhock5@gmail.com',
            'maudelaperriere@gmail.com',
            'rob@gmail.com some text steve@gmail.com',
            'a@b.com some text c@d.com and e@f.com',
            np.nan,
            "",
        ]
        expected_tuples = [
            ("dave", "google", "com"),
            ("tdhock5", "gmail", "com"),
            ("maudelaperriere", "gmail", "com"),
            ("rob", "gmail", "com"), ("steve", "gmail", "com"),
            ("a", "b", "com"), ("c", "d", "com"), ("e", "f", "com"),
        ]
        named_pattern = r"""
        (?P<user>[a-z0-9]+)
        @
        (?P<domain>[a-z]+)
        \.
        (?P<tld>[a-z]{2,4})
        """
        expected_columns = ["user", "domain", "tld"]
        S = Series(subject_list)
        # extractall should return a DataFrame with one row for each
        # match, indexed by the subject from which the match came.
        expected_index = MultiIndex.from_tuples([
            (0, 0),
            (1, 0),
            (2, 0),
            (3, 0),
            (3, 1),
            (4, 0),
            (4, 1),
            (4, 2),
        ], names=(None, "match"))
        expected_df = DataFrame(
            expected_tuples, expected_index, expected_columns)
        computed_df = S.str.extractall(named_pattern, re.VERBOSE)
        tm.assert_frame_equal(computed_df, expected_df)

        # The index of the input Series should be used to construct
        # the index of the output DataFrame:
        series_index = MultiIndex.from_tuples([
            ("single", "Dave"),
            ("single", "Toby"),
            ("single", "Maude"),
            ("multiple", "robAndSteve"),
            ("multiple", "abcdef"),
            ("none", "missing"),
            ("none", "empty"),
        ])
        Si = Series(subject_list, series_index)
        expected_index = MultiIndex.from_tuples([
            ("single", "Dave", 0),
            ("single", "Toby", 0),
            ("single", "Maude", 0),
            ("multiple", "robAndSteve", 0),
            ("multiple", "robAndSteve", 1),
            ("multiple", "abcdef", 0),
            ("multiple", "abcdef", 1),
            ("multiple", "abcdef", 2),
        ], names=(None, None, "match"))
        expected_df = DataFrame(
            expected_tuples, expected_index, expected_columns)
        computed_df = Si.str.extractall(named_pattern, re.VERBOSE)
        tm.assert_frame_equal(computed_df, expected_df)

        # MultiIndexed subject with names.
        Sn = Series(subject_list, series_index)
        Sn.index.names = ("matches", "description")
        expected_index.names = ("matches", "description", "match")
        expected_df = DataFrame(
            expected_tuples, expected_index, expected_columns)
        computed_df = Sn.str.extractall(named_pattern, re.VERBOSE)
        tm.assert_frame_equal(computed_df, expected_df)

        # optional groups.
        subject_list = ['', 'A1', '32']
        named_pattern = '(?P<letter>[AB])?(?P<number>[123])'
        computed_df = Series(subject_list).str.extractall(named_pattern)
        expected_index = MultiIndex.from_tuples([
            (1, 0),
            (2, 0),
            (2, 1),
        ], names=(None, "match"))
        expected_df = DataFrame([
            ('A', '1'),
            (NA, '3'),
            (NA, '2'),
        ], expected_index, columns=['letter', 'number'])
        tm.assert_frame_equal(computed_df, expected_df)

        # only one of two groups has a name.
        pattern = '([AB])?(?P<number>[123])'
        computed_df = Series(subject_list).str.extractall(pattern)
        expected_df = DataFrame([
            ('A', '1'),
            (NA, '3'),
            (NA, '2'),
        ], expected_index, columns=[0, 'number'])
        tm.assert_frame_equal(computed_df, expected_df)

    def test_extractall_single_group(self):
        # extractall(one named group) returns DataFrame with one named
        # column.
        s = Series(['a3', 'b3', 'd4c2'], name='series_name')
        r = s.str.extractall(r'(?P<letter>[a-z])')
        i = MultiIndex.from_tuples([
            (0, 0),
            (1, 0),
            (2, 0),
            (2, 1),
        ], names=(None, "match"))
        e = DataFrame({"letter": ['a', 'b', 'd', 'c']}, i)
        tm.assert_frame_equal(r, e)

        # extractall(one un-named group) returns DataFrame with one
        # un-named column.
        r = s.str.extractall(r'([a-z])')
        e = DataFrame(['a', 'b', 'd', 'c'], i)
        tm.assert_frame_equal(r, e)

    def test_extractall_single_group_with_quantifier(self):
        # extractall(one un-named group with quantifier) returns
        # DataFrame with one un-named column (GH13382).
        s = Series(['ab3', 'abc3', 'd4cd2'], name='series_name')
        r = s.str.extractall(r'([a-z]+)')
        i = MultiIndex.from_tuples([
            (0, 0),
            (1, 0),
            (2, 0),
            (2, 1),
        ], names=(None, "match"))
        e = DataFrame(['ab', 'abc', 'd', 'cd'], i)
        tm.assert_frame_equal(r, e)

    @pytest.mark.parametrize('data, names', [
        ([], (None, )),
        ([], ('i1', )),
        ([], (None, 'i2')),
        ([], ('i1', 'i2')),
        (['a3', 'b3', 'd4c2'], (None, )),
        (['a3', 'b3', 'd4c2'], ('i1', 'i2')),
        (['a3', 'b3', 'd4c2'], (None, 'i2')),
        (['a3', 'b3', 'd4c2'], ('i1', 'i2')),
    ])
    def test_extractall_no_matches(self, data, names):
        # GH19075 extractall with no matches should return a valid MultiIndex
        n = len(data)
        if len(names) == 1:
            i = Index(range(n), name=names[0])
        else:
            a = (tuple([i] * (n - 1)) for i in range(n))
            i = MultiIndex.from_tuples(a, names=names)
        s = Series(data, name='series_name', index=i, dtype='object')
        ei = MultiIndex.from_tuples([], names=(names + ('match',)))

        # one un-named group.
        r = s.str.extractall('(z)')
        e = DataFrame(columns=[0], index=ei)
        tm.assert_frame_equal(r, e)

        # two un-named groups.
        r = s.str.extractall('(z)(z)')
        e = DataFrame(columns=[0, 1], index=ei)
        tm.assert_frame_equal(r, e)

        # one named group.
        r = s.str.extractall('(?P<first>z)')
        e = DataFrame(columns=["first"], index=ei)
        tm.assert_frame_equal(r, e)

        # two named groups.
        r = s.str.extractall('(?P<first>z)(?P<second>z)')
        e = DataFrame(columns=["first", "second"], index=ei)
        tm.assert_frame_equal(r, e)

        # one named, one un-named.
        r = s.str.extractall('(z)(?P<second>z)')
        e = DataFrame(columns=[0, "second"], index=ei)
        tm.assert_frame_equal(r, e)

    def test_extractall_stringindex(self):
        s = Series(["a1a2", "b1", "c1"], name='xxx')
        res = s.str.extractall(r"[ab](?P<digit>\d)")
        exp_idx = MultiIndex.from_tuples([(0, 0), (0, 1), (1, 0)],
                                         names=[None, 'match'])
        exp = DataFrame({'digit': ["1", "2", "1"]}, index=exp_idx)
        tm.assert_frame_equal(res, exp)

        # index should return the same result as the default index without name
        # thus index.name doesn't affect to the result
        for idx in [Index(["a1a2", "b1", "c1"]),
                    Index(["a1a2", "b1", "c1"], name='xxx')]:

            res = idx.str.extractall(r"[ab](?P<digit>\d)")
            tm.assert_frame_equal(res, exp)

        s = Series(["a1a2", "b1", "c1"], name='s_name',
                   index=Index(["XX", "yy", "zz"], name='idx_name'))
        res = s.str.extractall(r"[ab](?P<digit>\d)")
        exp_idx = MultiIndex.from_tuples([("XX", 0), ("XX", 1), ("yy", 0)],
                                         names=["idx_name", 'match'])
        exp = DataFrame({'digit': ["1", "2", "1"]}, index=exp_idx)
        tm.assert_frame_equal(res, exp)

    def test_extractall_errors(self):
        # Does not make sense to use extractall with a regex that has
        # no capture groups. (it returns DataFrame with one column for
        # each capture group)
        s = Series(['a3', 'b3', 'd4c2'], name='series_name')
        with pytest.raises(ValueError, match="no capture groups"):
            s.str.extractall(r'[a-z]')

    def test_extract_index_one_two_groups(self):
        s = Series(['a3', 'b3', 'd4c2'], index=["A3", "B3", "D4"],
                   name='series_name')
        r = s.index.str.extract(r'([A-Z])', expand=True)
        e = DataFrame(['A', "B", "D"])
        tm.assert_frame_equal(r, e)

        # Prior to v0.18.0, index.str.extract(regex with one group)
        # returned Index. With more than one group, extract raised an
        # error (GH9980). Now extract always returns DataFrame.
        r = s.index.str.extract(
            r'(?P<letter>[A-Z])(?P<digit>[0-9])', expand=True)
        e_list = [
            ("A", "3"),
            ("B", "3"),
            ("D", "4"),
        ]
        e = DataFrame(e_list, columns=["letter", "digit"])
        tm.assert_frame_equal(r, e)

    def test_extractall_same_as_extract(self):
        s = Series(['a3', 'b3', 'c2'], name='series_name')

        pattern_two_noname = r'([a-z])([0-9])'
        extract_two_noname = s.str.extract(pattern_two_noname, expand=True)
        has_multi_index = s.str.extractall(pattern_two_noname)
        no_multi_index = has_multi_index.xs(0, level="match")
        tm.assert_frame_equal(extract_two_noname, no_multi_index)

        pattern_two_named = r'(?P<letter>[a-z])(?P<digit>[0-9])'
        extract_two_named = s.str.extract(pattern_two_named, expand=True)
        has_multi_index = s.str.extractall(pattern_two_named)
        no_multi_index = has_multi_index.xs(0, level="match")
        tm.assert_frame_equal(extract_two_named, no_multi_index)

        pattern_one_named = r'(?P<group_name>[a-z])'
        extract_one_named = s.str.extract(pattern_one_named, expand=True)
        has_multi_index = s.str.extractall(pattern_one_named)
        no_multi_index = has_multi_index.xs(0, level="match")
        tm.assert_frame_equal(extract_one_named, no_multi_index)

        pattern_one_noname = r'([a-z])'
        extract_one_noname = s.str.extract(pattern_one_noname, expand=True)
        has_multi_index = s.str.extractall(pattern_one_noname)
        no_multi_index = has_multi_index.xs(0, level="match")
        tm.assert_frame_equal(extract_one_noname, no_multi_index)

    def test_extractall_same_as_extract_subject_index(self):
        # same as above tests, but s has an MultiIndex.
        i = MultiIndex.from_tuples([
            ("A", "first"),
            ("B", "second"),
            ("C", "third"),
        ], names=("capital", "ordinal"))
        s = Series(['a3', 'b3', 'c2'], i, name='series_name')

        pattern_two_noname = r'([a-z])([0-9])'
        extract_two_noname = s.str.extract(pattern_two_noname, expand=True)
        has_match_index = s.str.extractall(pattern_two_noname)
        no_match_index = has_match_index.xs(0, level="match")
        tm.assert_frame_equal(extract_two_noname, no_match_index)

        pattern_two_named = r'(?P<letter>[a-z])(?P<digit>[0-9])'
        extract_two_named = s.str.extract(pattern_two_named, expand=True)
        has_match_index = s.str.extractall(pattern_two_named)
        no_match_index = has_match_index.xs(0, level="match")
        tm.assert_frame_equal(extract_two_named, no_match_index)

        pattern_one_named = r'(?P<group_name>[a-z])'
        extract_one_named = s.str.extract(pattern_one_named, expand=True)
        has_match_index = s.str.extractall(pattern_one_named)
        no_match_index = has_match_index.xs(0, level="match")
        tm.assert_frame_equal(extract_one_named, no_match_index)

        pattern_one_noname = r'([a-z])'
        extract_one_noname = s.str.extract(pattern_one_noname, expand=True)
        has_match_index = s.str.extractall(pattern_one_noname)
        no_match_index = has_match_index.xs(0, level="match")
        tm.assert_frame_equal(extract_one_noname, no_match_index)

    def test_empty_str_methods(self):
        empty_str = empty = Series(dtype=object)
        empty_int = Series(dtype=int)
        empty_bool = Series(dtype=bool)
        empty_bytes = Series(dtype=object)

        # GH7241
        # (extract) on empty series

        tm.assert_series_equal(empty_str, empty.str.cat(empty))
        assert '' == empty.str.cat()
        tm.assert_series_equal(empty_str, empty.str.title())
        tm.assert_series_equal(empty_int, empty.str.count('a'))
        tm.assert_series_equal(empty_bool, empty.str.contains('a'))
        tm.assert_series_equal(empty_bool, empty.str.startswith('a'))
        tm.assert_series_equal(empty_bool, empty.str.endswith('a'))
        tm.assert_series_equal(empty_str, empty.str.lower())
        tm.assert_series_equal(empty_str, empty.str.upper())
        tm.assert_series_equal(empty_str, empty.str.replace('a', 'b'))
        tm.assert_series_equal(empty_str, empty.str.repeat(3))
        tm.assert_series_equal(empty_bool, empty.str.match('^a'))
        tm.assert_frame_equal(
            DataFrame(columns=[0], dtype=str),
            empty.str.extract('()', expand=True))
        tm.assert_frame_equal(
            DataFrame(columns=[0, 1], dtype=str),
            empty.str.extract('()()', expand=True))
        tm.assert_series_equal(
            empty_str,
            empty.str.extract('()', expand=False))
        tm.assert_frame_equal(
            DataFrame(columns=[0, 1], dtype=str),
            empty.str.extract('()()', expand=False))
        tm.assert_frame_equal(DataFrame(dtype=str), empty.str.get_dummies())
        tm.assert_series_equal(empty_str, empty_str.str.join(''))
        tm.assert_series_equal(empty_int, empty.str.len())
        tm.assert_series_equal(empty_str, empty_str.str.findall('a'))
        tm.assert_series_equal(empty_int, empty.str.find('a'))
        tm.assert_series_equal(empty_int, empty.str.rfind('a'))
        tm.assert_series_equal(empty_str, empty.str.pad(42))
        tm.assert_series_equal(empty_str, empty.str.center(42))
        tm.assert_series_equal(empty_str, empty.str.split('a'))
        tm.assert_series_equal(empty_str, empty.str.rsplit('a'))
        tm.assert_series_equal(empty_str,
                               empty.str.partition('a', expand=False))
        tm.assert_series_equal(empty_str,
                               empty.str.rpartition('a', expand=False))
        tm.assert_series_equal(empty_str, empty.str.slice(stop=1))
        tm.assert_series_equal(empty_str, empty.str.slice(step=1))
        tm.assert_series_equal(empty_str, empty.str.strip())
        tm.assert_series_equal(empty_str, empty.str.lstrip())
        tm.assert_series_equal(empty_str, empty.str.rstrip())
        tm.assert_series_equal(empty_str, empty.str.wrap(42))
        tm.assert_series_equal(empty_str, empty.str.get(0))
        tm.assert_series_equal(empty_str, empty_bytes.str.decode('ascii'))
        tm.assert_series_equal(empty_bytes, empty.str.encode('ascii'))
        tm.assert_series_equal(empty_str, empty.str.isalnum())
        tm.assert_series_equal(empty_str, empty.str.isalpha())
        tm.assert_series_equal(empty_str, empty.str.isdigit())
        tm.assert_series_equal(empty_str, empty.str.isspace())
        tm.assert_series_equal(empty_str, empty.str.islower())
        tm.assert_series_equal(empty_str, empty.str.isupper())
        tm.assert_series_equal(empty_str, empty.str.istitle())
        tm.assert_series_equal(empty_str, empty.str.isnumeric())
        tm.assert_series_equal(empty_str, empty.str.isdecimal())
        tm.assert_series_equal(empty_str, empty.str.capitalize())
        tm.assert_series_equal(empty_str, empty.str.swapcase())
        tm.assert_series_equal(empty_str, empty.str.normalize('NFC'))
        if compat.PY3:
            table = str.maketrans('a', 'b')
        else:
            import string
            table = string.maketrans('a', 'b')
        tm.assert_series_equal(empty_str, empty.str.translate(table))

    def test_empty_str_methods_to_frame(self):
        empty = Series(dtype=str)
        empty_df = DataFrame([])
        tm.assert_frame_equal(empty_df, empty.str.partition('a'))
        tm.assert_frame_equal(empty_df, empty.str.rpartition('a'))

    def test_ismethods(self):
        values = ['A', 'b', 'Xy', '4', '3A', '', 'TT', '55', '-', '  ']
        str_s = Series(values)
        alnum_e = [True, True, True, True, True, False, True, True, False,
                   False]
        alpha_e = [True, True, True, False, False, False, True, False, False,
                   False]
        digit_e = [False, False, False, True, False, False, False, True, False,
                   False]

        # TODO: unused
        num_e = [False, False, False, True, False, False,  # noqa
                 False, True, False, False]

        space_e = [False, False, False, False, False, False, False, False,
                   False, True]
        lower_e = [False, True, False, False, False, False, False, False,
                   False, False]
        upper_e = [True, False, False, False, True, False, True, False, False,
                   False]
        title_e = [True, False, True, False, True, False, False, False, False,
                   False]

        tm.assert_series_equal(str_s.str.isalnum(), Series(alnum_e))
        tm.assert_series_equal(str_s.str.isalpha(), Series(alpha_e))
        tm.assert_series_equal(str_s.str.isdigit(), Series(digit_e))
        tm.assert_series_equal(str_s.str.isspace(), Series(space_e))
        tm.assert_series_equal(str_s.str.islower(), Series(lower_e))
        tm.assert_series_equal(str_s.str.isupper(), Series(upper_e))
        tm.assert_series_equal(str_s.str.istitle(), Series(title_e))

        assert str_s.str.isalnum().tolist() == [v.isalnum() for v in values]
        assert str_s.str.isalpha().tolist() == [v.isalpha() for v in values]
        assert str_s.str.isdigit().tolist() == [v.isdigit() for v in values]
        assert str_s.str.isspace().tolist() == [v.isspace() for v in values]
        assert str_s.str.islower().tolist() == [v.islower() for v in values]
        assert str_s.str.isupper().tolist() == [v.isupper() for v in values]
        assert str_s.str.istitle().tolist() == [v.istitle() for v in values]

    def test_isnumeric(self):
        # 0x00bc: ¼ VULGAR FRACTION ONE QUARTER
        # 0x2605: ★ not number
        # 0x1378: ፸ ETHIOPIC NUMBER SEVENTY
        # 0xFF13: ３ Em 3
        values = ['A', '3', u'¼', u'★', u'፸', u'３', 'four']
        s = Series(values)
        numeric_e = [False, True, True, False, True, True, False]
        decimal_e = [False, True, False, False, False, True, False]
        tm.assert_series_equal(s.str.isnumeric(), Series(numeric_e))
        tm.assert_series_equal(s.str.isdecimal(), Series(decimal_e))

        unicodes = [u'A', u'3', u'¼', u'★', u'፸', u'３', u'four']
        assert s.str.isnumeric().tolist() == [v.isnumeric() for v in unicodes]
        assert s.str.isdecimal().tolist() == [v.isdecimal() for v in unicodes]

        values = ['A', np.nan, u'¼', u'★', np.nan, u'３', 'four']
        s = Series(values)
        numeric_e = [False, np.nan, True, False, np.nan, True, False]
        decimal_e = [False, np.nan, False, False, np.nan, True, False]
        tm.assert_series_equal(s.str.isnumeric(), Series(numeric_e))
        tm.assert_series_equal(s.str.isdecimal(), Series(decimal_e))

    def test_get_dummies(self):
        s = Series(['a|b', 'a|c', np.nan])
        result = s.str.get_dummies('|')
        expected = DataFrame([[1, 1, 0], [1, 0, 1], [0, 0, 0]],
                             columns=list('abc'))
        tm.assert_frame_equal(result, expected)

        s = Series(['a;b', 'a', 7])
        result = s.str.get_dummies(';')
        expected = DataFrame([[0, 1, 1], [0, 1, 0], [1, 0, 0]],
                             columns=list('7ab'))
        tm.assert_frame_equal(result, expected)

        # GH9980, GH8028
        idx = Index(['a|b', 'a|c', 'b|c'])
        result = idx.str.get_dummies('|')

        expected = MultiIndex.from_tuples([(1, 1, 0), (1, 0, 1),
                                           (0, 1, 1)], names=('a', 'b', 'c'))
        tm.assert_index_equal(result, expected)

    def test_get_dummies_with_name_dummy(self):
        # GH 12180
        # Dummies named 'name' should work as expected
        s = Series(['a', 'b,name', 'b'])
        result = s.str.get_dummies(',')
        expected = DataFrame([[1, 0, 0], [0, 1, 1], [0, 1, 0]],
                             columns=['a', 'b', 'name'])
        tm.assert_frame_equal(result, expected)

        idx = Index(['a|b', 'name|c', 'b|name'])
        result = idx.str.get_dummies('|')

        expected = MultiIndex.from_tuples([(1, 1, 0, 0), (0, 0, 1, 1),
                                           (0, 1, 0, 1)],
                                          names=('a', 'b', 'c', 'name'))
        tm.assert_index_equal(result, expected)

    def test_join(self):
        values = Series(['a_b_c', 'c_d_e', np.nan, 'f_g_h'])
        result = values.str.split('_').str.join('_')
        tm.assert_series_equal(values, result)

        # mixed
        mixed = Series(['a_b', NA, 'asdf_cas_asdf', True, datetime.today(),
                        'foo', None, 1, 2.])

        rs = Series(mixed).str.split('_').str.join('_')
        xp = Series(['a_b', NA, 'asdf_cas_asdf', NA, NA, 'foo', NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('a_b_c'), u('c_d_e'), np.nan, u('f_g_h')])
        result = values.str.split('_').str.join('_')
        tm.assert_series_equal(values, result)

    def test_len(self):
        values = Series(['foo', 'fooo', 'fooooo', np.nan, 'fooooooo'])

        result = values.str.len()
        exp = values.map(lambda x: len(x) if notna(x) else NA)
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['a_b', NA, 'asdf_cas_asdf', True, datetime.today(),
                        'foo', None, 1, 2.])

        rs = Series(mixed).str.len()
        xp = Series([3, NA, 13, NA, NA, 3, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('foo'), u('fooo'), u('fooooo'), np.nan, u(
            'fooooooo')])

        result = values.str.len()
        exp = values.map(lambda x: len(x) if notna(x) else NA)
        tm.assert_series_equal(result, exp)

    def test_findall(self):
        values = Series(['fooBAD__barBAD', NA, 'foo', 'BAD'])

        result = values.str.findall('BAD[_]*')
        exp = Series([['BAD__', 'BAD'], NA, [], ['BAD']])
        tm.assert_almost_equal(result, exp)

        # mixed
        mixed = Series(['fooBAD__barBAD', NA, 'foo', True, datetime.today(),
                        'BAD', None, 1, 2.])

        rs = Series(mixed).str.findall('BAD[_]*')
        xp = Series([['BAD__', 'BAD'], NA, [], NA, NA, ['BAD'], NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('fooBAD__barBAD'), NA, u('foo'), u('BAD')])

        result = values.str.findall('BAD[_]*')
        exp = Series([[u('BAD__'), u('BAD')], NA, [], [u('BAD')]])
        tm.assert_almost_equal(result, exp)

    def test_find(self):
        values = Series(['ABCDEFG', 'BCDEFEF', 'DEFGHIJEF', 'EFGHEF', 'XXXX'])
        result = values.str.find('EF')
        tm.assert_series_equal(result, Series([4, 3, 1, 0, -1]))
        expected = np.array([v.find('EF') for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.rfind('EF')
        tm.assert_series_equal(result, Series([4, 5, 7, 4, -1]))
        expected = np.array([v.rfind('EF') for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.find('EF', 3)
        tm.assert_series_equal(result, Series([4, 3, 7, 4, -1]))
        expected = np.array([v.find('EF', 3) for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.rfind('EF', 3)
        tm.assert_series_equal(result, Series([4, 5, 7, 4, -1]))
        expected = np.array([v.rfind('EF', 3) for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.find('EF', 3, 6)
        tm.assert_series_equal(result, Series([4, 3, -1, 4, -1]))
        expected = np.array([v.find('EF', 3, 6) for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.rfind('EF', 3, 6)
        tm.assert_series_equal(result, Series([4, 3, -1, 4, -1]))
        expected = np.array([v.rfind('EF', 3, 6) for v in values.values],
                            dtype=np.int64)
        tm.assert_numpy_array_equal(result.values, expected)

        with pytest.raises(TypeError,
                           match="expected a string object, not int"):
            result = values.str.find(0)

        with pytest.raises(TypeError,
                           match="expected a string object, not int"):
            result = values.str.rfind(0)

    def test_find_nan(self):
        values = Series(['ABCDEFG', np.nan, 'DEFGHIJEF', np.nan, 'XXXX'])
        result = values.str.find('EF')
        tm.assert_series_equal(result, Series([4, np.nan, 1, np.nan, -1]))

        result = values.str.rfind('EF')
        tm.assert_series_equal(result, Series([4, np.nan, 7, np.nan, -1]))

        result = values.str.find('EF', 3)
        tm.assert_series_equal(result, Series([4, np.nan, 7, np.nan, -1]))

        result = values.str.rfind('EF', 3)
        tm.assert_series_equal(result, Series([4, np.nan, 7, np.nan, -1]))

        result = values.str.find('EF', 3, 6)
        tm.assert_series_equal(result, Series([4, np.nan, -1, np.nan, -1]))

        result = values.str.rfind('EF', 3, 6)
        tm.assert_series_equal(result, Series([4, np.nan, -1, np.nan, -1]))

    def test_index(self):

        def _check(result, expected):
            if isinstance(result, Series):
                tm.assert_series_equal(result, expected)
            else:
                tm.assert_index_equal(result, expected)

        for klass in [Series, Index]:
            s = klass(['ABCDEFG', 'BCDEFEF', 'DEFGHIJEF', 'EFGHEF'])

            result = s.str.index('EF')
            _check(result, klass([4, 3, 1, 0]))
            expected = np.array([v.index('EF') for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            result = s.str.rindex('EF')
            _check(result, klass([4, 5, 7, 4]))
            expected = np.array([v.rindex('EF') for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            result = s.str.index('EF', 3)
            _check(result, klass([4, 3, 7, 4]))
            expected = np.array([v.index('EF', 3) for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            result = s.str.rindex('EF', 3)
            _check(result, klass([4, 5, 7, 4]))
            expected = np.array([v.rindex('EF', 3) for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            result = s.str.index('E', 4, 8)
            _check(result, klass([4, 5, 7, 4]))
            expected = np.array([v.index('E', 4, 8) for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            result = s.str.rindex('E', 0, 5)
            _check(result, klass([4, 3, 1, 4]))
            expected = np.array([v.rindex('E', 0, 5) for v in s.values],
                                dtype=np.int64)
            tm.assert_numpy_array_equal(result.values, expected)

            with pytest.raises(ValueError, match="substring not found"):
                result = s.str.index('DE')

            msg = "expected a string object, not int"
            with pytest.raises(TypeError, match=msg):
                result = s.str.index(0)

        # test with nan
        s = Series(['abcb', 'ab', 'bcbe', np.nan])
        result = s.str.index('b')
        tm.assert_series_equal(result, Series([1, 1, 0, np.nan]))
        result = s.str.rindex('b')
        tm.assert_series_equal(result, Series([3, 1, 2, np.nan]))

    def test_pad(self):
        values = Series(['a', 'b', NA, 'c', NA, 'eeeeee'])

        result = values.str.pad(5, side='left')
        exp = Series(['    a', '    b', NA, '    c', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='right')
        exp = Series(['a    ', 'b    ', NA, 'c    ', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='both')
        exp = Series(['  a  ', '  b  ', NA, '  c  ', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        # mixed
        mixed = Series(['a', NA, 'b', True, datetime.today(), 'ee', None, 1, 2.
                        ])

        rs = Series(mixed).str.pad(5, side='left')
        xp = Series(['    a', NA, '    b', NA, NA, '   ee', NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        mixed = Series(['a', NA, 'b', True, datetime.today(), 'ee', None, 1, 2.
                        ])

        rs = Series(mixed).str.pad(5, side='right')
        xp = Series(['a    ', NA, 'b    ', NA, NA, 'ee   ', NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        mixed = Series(['a', NA, 'b', True, datetime.today(), 'ee', None, 1, 2.
                        ])

        rs = Series(mixed).str.pad(5, side='both')
        xp = Series(['  a  ', NA, '  b  ', NA, NA, '  ee ', NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('a'), u('b'), NA, u('c'), NA, u('eeeeee')])

        result = values.str.pad(5, side='left')
        exp = Series([u('    a'), u('    b'), NA, u('    c'), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='right')
        exp = Series([u('a    '), u('b    '), NA, u('c    '), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='both')
        exp = Series([u('  a  '), u('  b  '), NA, u('  c  '), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

    def test_pad_fillchar(self):

        values = Series(['a', 'b', NA, 'c', NA, 'eeeeee'])

        result = values.str.pad(5, side='left', fillchar='X')
        exp = Series(['XXXXa', 'XXXXb', NA, 'XXXXc', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='right', fillchar='X')
        exp = Series(['aXXXX', 'bXXXX', NA, 'cXXXX', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.pad(5, side='both', fillchar='X')
        exp = Series(['XXaXX', 'XXbXX', NA, 'XXcXX', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        msg = "fillchar must be a character, not str"
        with pytest.raises(TypeError, match=msg):
            result = values.str.pad(5, fillchar='XY')

        msg = "fillchar must be a character, not int"
        with pytest.raises(TypeError, match=msg):
            result = values.str.pad(5, fillchar=5)

    @pytest.mark.parametrize("f", ['center', 'ljust', 'rjust', 'zfill', 'pad'])
    def test_pad_width(self, f):
        # see gh-13598
        s = Series(['1', '22', 'a', 'bb'])
        msg = "width must be of integer type, not*"

        with pytest.raises(TypeError, match=msg):
            getattr(s.str, f)('f')

    def test_translate(self):

        def _check(result, expected):
            if isinstance(result, Series):
                tm.assert_series_equal(result, expected)
            else:
                tm.assert_index_equal(result, expected)

        for klass in [Series, Index]:
            s = klass(['abcdefg', 'abcc', 'cdddfg', 'cdefggg'])
            if not compat.PY3:
                import string
                table = string.maketrans('abc', 'cde')
            else:
                table = str.maketrans('abc', 'cde')
            result = s.str.translate(table)
            expected = klass(['cdedefg', 'cdee', 'edddfg', 'edefggg'])
            _check(result, expected)

            # use of deletechars is python 2 only
            if not compat.PY3:
                result = s.str.translate(table, deletechars='fg')
                expected = klass(['cdede', 'cdee', 'eddd', 'ede'])
                _check(result, expected)

                result = s.str.translate(None, deletechars='fg')
                expected = klass(['abcde', 'abcc', 'cddd', 'cde'])
                _check(result, expected)
            else:
                msg = "deletechars is not a valid argument"
                with pytest.raises(ValueError, match=msg):
                    result = s.str.translate(table, deletechars='fg')

        # Series with non-string values
        s = Series(['a', 'b', 'c', 1.2])
        expected = Series(['c', 'd', 'e', np.nan])
        result = s.str.translate(table)
        tm.assert_series_equal(result, expected)

    def test_center_ljust_rjust(self):
        values = Series(['a', 'b', NA, 'c', NA, 'eeeeee'])

        result = values.str.center(5)
        exp = Series(['  a  ', '  b  ', NA, '  c  ', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.ljust(5)
        exp = Series(['a    ', 'b    ', NA, 'c    ', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        result = values.str.rjust(5)
        exp = Series(['    a', '    b', NA, '    c', NA, 'eeeeee'])
        tm.assert_almost_equal(result, exp)

        # mixed
        mixed = Series(['a', NA, 'b', True, datetime.today(), 'c', 'eee', None,
                        1, 2.])

        rs = Series(mixed).str.center(5)
        xp = Series(['  a  ', NA, '  b  ', NA, NA, '  c  ', ' eee ', NA, NA, NA
                     ])
        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        rs = Series(mixed).str.ljust(5)
        xp = Series(['a    ', NA, 'b    ', NA, NA, 'c    ', 'eee  ', NA, NA, NA
                     ])
        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        rs = Series(mixed).str.rjust(5)
        xp = Series(['    a', NA, '    b', NA, NA, '    c', '  eee', NA, NA, NA
                     ])
        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('a'), u('b'), NA, u('c'), NA, u('eeeeee')])

        result = values.str.center(5)
        exp = Series([u('  a  '), u('  b  '), NA, u('  c  '), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

        result = values.str.ljust(5)
        exp = Series([u('a    '), u('b    '), NA, u('c    '), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

        result = values.str.rjust(5)
        exp = Series([u('    a'), u('    b'), NA, u('    c'), NA, u('eeeeee')])
        tm.assert_almost_equal(result, exp)

    def test_center_ljust_rjust_fillchar(self):
        values = Series(['a', 'bb', 'cccc', 'ddddd', 'eeeeee'])

        result = values.str.center(5, fillchar='X')
        expected = Series(['XXaXX', 'XXbbX', 'Xcccc', 'ddddd', 'eeeeee'])
        tm.assert_series_equal(result, expected)
        expected = np.array([v.center(5, 'X') for v in values.values],
                            dtype=np.object_)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.ljust(5, fillchar='X')
        expected = Series(['aXXXX', 'bbXXX', 'ccccX', 'ddddd', 'eeeeee'])
        tm.assert_series_equal(result, expected)
        expected = np.array([v.ljust(5, 'X') for v in values.values],
                            dtype=np.object_)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.rjust(5, fillchar='X')
        expected = Series(['XXXXa', 'XXXbb', 'Xcccc', 'ddddd', 'eeeeee'])
        tm.assert_series_equal(result, expected)
        expected = np.array([v.rjust(5, 'X') for v in values.values],
                            dtype=np.object_)
        tm.assert_numpy_array_equal(result.values, expected)

        # If fillchar is not a charatter, normal str raises TypeError
        # 'aaa'.ljust(5, 'XY')
        # TypeError: must be char, not str
        template = "fillchar must be a character, not {dtype}"

        with pytest.raises(TypeError, match=template.format(dtype="str")):
            values.str.center(5, fillchar='XY')

        with pytest.raises(TypeError, match=template.format(dtype="str")):
            values.str.ljust(5, fillchar='XY')

        with pytest.raises(TypeError, match=template.format(dtype="str")):
            values.str.rjust(5, fillchar='XY')

        with pytest.raises(TypeError, match=template.format(dtype="int")):
            values.str.center(5, fillchar=1)

        with pytest.raises(TypeError, match=template.format(dtype="int")):
            values.str.ljust(5, fillchar=1)

        with pytest.raises(TypeError, match=template.format(dtype="int")):
            values.str.rjust(5, fillchar=1)

    def test_zfill(self):
        values = Series(['1', '22', 'aaa', '333', '45678'])

        result = values.str.zfill(5)
        expected = Series(['00001', '00022', '00aaa', '00333', '45678'])
        tm.assert_series_equal(result, expected)
        expected = np.array([v.zfill(5) for v in values.values],
                            dtype=np.object_)
        tm.assert_numpy_array_equal(result.values, expected)

        result = values.str.zfill(3)
        expected = Series(['001', '022', 'aaa', '333', '45678'])
        tm.assert_series_equal(result, expected)
        expected = np.array([v.zfill(3) for v in values.values],
                            dtype=np.object_)
        tm.assert_numpy_array_equal(result.values, expected)

        values = Series(['1', np.nan, 'aaa', np.nan, '45678'])
        result = values.str.zfill(5)
        expected = Series(['00001', np.nan, '00aaa', np.nan, '45678'])
        tm.assert_series_equal(result, expected)

    def test_split(self):
        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h'])

        result = values.str.split('_')
        exp = Series([['a', 'b', 'c'], ['c', 'd', 'e'], NA, ['f', 'g', 'h']])
        tm.assert_series_equal(result, exp)

        # more than one char
        values = Series(['a__b__c', 'c__d__e', NA, 'f__g__h'])
        result = values.str.split('__')
        tm.assert_series_equal(result, exp)

        result = values.str.split('__', expand=False)
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['a_b_c', NA, 'd_e_f', True, datetime.today(), None, 1,
                        2.])
        result = mixed.str.split('_')
        exp = Series([['a', 'b', 'c'], NA, ['d', 'e', 'f'], NA, NA, NA, NA, NA
                      ])
        assert isinstance(result, Series)
        tm.assert_almost_equal(result, exp)

        result = mixed.str.split('_', expand=False)
        assert isinstance(result, Series)
        tm.assert_almost_equal(result, exp)

        # unicode
        values = Series([u('a_b_c'), u('c_d_e'), NA, u('f_g_h')])

        result = values.str.split('_')
        exp = Series([[u('a'), u('b'), u('c')], [u('c'), u('d'), u('e')], NA,
                      [u('f'), u('g'), u('h')]])
        tm.assert_series_equal(result, exp)

        result = values.str.split('_', expand=False)
        tm.assert_series_equal(result, exp)

        # regex split
        values = Series([u('a,b_c'), u('c_d,e'), NA, u('f,g,h')])
        result = values.str.split('[,_]')
        exp = Series([[u('a'), u('b'), u('c')], [u('c'), u('d'), u('e')], NA,
                      [u('f'), u('g'), u('h')]])
        tm.assert_series_equal(result, exp)

    def test_rsplit(self):
        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h'])
        result = values.str.rsplit('_')
        exp = Series([['a', 'b', 'c'], ['c', 'd', 'e'], NA, ['f', 'g', 'h']])
        tm.assert_series_equal(result, exp)

        # more than one char
        values = Series(['a__b__c', 'c__d__e', NA, 'f__g__h'])
        result = values.str.rsplit('__')
        tm.assert_series_equal(result, exp)

        result = values.str.rsplit('__', expand=False)
        tm.assert_series_equal(result, exp)

        # mixed
        mixed = Series(['a_b_c', NA, 'd_e_f', True, datetime.today(), None, 1,
                        2.])
        result = mixed.str.rsplit('_')
        exp = Series([['a', 'b', 'c'], NA, ['d', 'e', 'f'], NA, NA, NA, NA, NA
                      ])
        assert isinstance(result, Series)
        tm.assert_almost_equal(result, exp)

        result = mixed.str.rsplit('_', expand=False)
        assert isinstance(result, Series)
        tm.assert_almost_equal(result, exp)

        # unicode
        values = Series([u('a_b_c'), u('c_d_e'), NA, u('f_g_h')])
        result = values.str.rsplit('_')
        exp = Series([[u('a'), u('b'), u('c')], [u('c'), u('d'), u('e')], NA,
                      [u('f'), u('g'), u('h')]])
        tm.assert_series_equal(result, exp)

        result = values.str.rsplit('_', expand=False)
        tm.assert_series_equal(result, exp)

        # regex split is not supported by rsplit
        values = Series([u('a,b_c'), u('c_d,e'), NA, u('f,g,h')])
        result = values.str.rsplit('[,_]')
        exp = Series([[u('a,b_c')], [u('c_d,e')], NA, [u('f,g,h')]])
        tm.assert_series_equal(result, exp)

        # setting max number of splits, make sure it's from reverse
        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h'])
        result = values.str.rsplit('_', n=1)
        exp = Series([['a_b', 'c'], ['c_d', 'e'], NA, ['f_g', 'h']])
        tm.assert_series_equal(result, exp)

    def test_split_blank_string(self):
        # expand blank split GH 20067
        values = Series([''], name='test')
        result = values.str.split(expand=True)
        exp = DataFrame([[]])
        tm.assert_frame_equal(result, exp)

        values = Series(['a b c', 'a b', '', ' '], name='test')
        result = values.str.split(expand=True)
        exp = DataFrame([['a', 'b', 'c'], ['a', 'b', np.nan],
                         [np.nan, np.nan, np.nan], [np.nan, np.nan, np.nan]])
        tm.assert_frame_equal(result, exp)

    def test_split_noargs(self):
        # #1859
        s = Series(['Wes McKinney', 'Travis  Oliphant'])
        result = s.str.split()
        expected = ['Travis', 'Oliphant']
        assert result[1] == expected
        result = s.str.rsplit()
        assert result[1] == expected

    def test_split_maxsplit(self):
        # re.split 0, str.split -1
        s = Series(['bd asdf jfg', 'kjasdflqw asdfnfk'])

        result = s.str.split(n=-1)
        xp = s.str.split()
        tm.assert_series_equal(result, xp)

        result = s.str.split(n=0)
        tm.assert_series_equal(result, xp)

        xp = s.str.split('asdf')
        result = s.str.split('asdf', n=0)
        tm.assert_series_equal(result, xp)

        result = s.str.split('asdf', n=-1)
        tm.assert_series_equal(result, xp)

    def test_split_no_pat_with_nonzero_n(self):
        s = Series(['split once', 'split once too!'])
        result = s.str.split(n=1)
        expected = Series({0: ['split', 'once'], 1: ['split', 'once too!']})
        tm.assert_series_equal(expected, result, check_index_type=False)

    def test_split_to_dataframe(self):
        s = Series(['nosplit', 'alsonosplit'])
        result = s.str.split('_', expand=True)
        exp = DataFrame({0: Series(['nosplit', 'alsonosplit'])})
        tm.assert_frame_equal(result, exp)

        s = Series(['some_equal_splits', 'with_no_nans'])
        result = s.str.split('_', expand=True)
        exp = DataFrame({0: ['some', 'with'],
                         1: ['equal', 'no'],
                         2: ['splits', 'nans']})
        tm.assert_frame_equal(result, exp)

        s = Series(['some_unequal_splits', 'one_of_these_things_is_not'])
        result = s.str.split('_', expand=True)
        exp = DataFrame({0: ['some', 'one'],
                         1: ['unequal', 'of'],
                         2: ['splits', 'these'],
                         3: [NA, 'things'],
                         4: [NA, 'is'],
                         5: [NA, 'not']})
        tm.assert_frame_equal(result, exp)

        s = Series(['some_splits', 'with_index'], index=['preserve', 'me'])
        result = s.str.split('_', expand=True)
        exp = DataFrame({0: ['some', 'with'], 1: ['splits', 'index']},
                        index=['preserve', 'me'])
        tm.assert_frame_equal(result, exp)

        with pytest.raises(ValueError, match="expand must be"):
            s.str.split('_', expand="not_a_boolean")

    def test_split_to_multiindex_expand(self):
        # https://github.com/pandas-dev/pandas/issues/23677

        idx = Index(['nosplit', 'alsonosplit', np.nan])
        result = idx.str.split('_', expand=True)
        exp = idx
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 1

        idx = Index(['some_equal_splits', 'with_no_nans', np.nan, None])
        result = idx.str.split('_', expand=True)
        exp = MultiIndex.from_tuples([('some', 'equal', 'splits'),
                                      ('with', 'no', 'nans'),
                                      [np.nan, np.nan, np.nan],
                                      [None, None, None]])
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 3

        idx = Index(['some_unequal_splits',
                     'one_of_these_things_is_not',
                     np.nan, None])
        result = idx.str.split('_', expand=True)
        exp = MultiIndex.from_tuples([('some', 'unequal', 'splits',
                                       NA, NA, NA),
                                      ('one', 'of', 'these',
                                       'things', 'is', 'not'),
                                      (np.nan, np.nan, np.nan,
                                       np.nan, np.nan, np.nan),
                                      (None, None, None,
                                       None, None, None)])
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 6

        with pytest.raises(ValueError, match="expand must be"):
            idx.str.split('_', expand="not_a_boolean")

    def test_rsplit_to_dataframe_expand(self):
        s = Series(['nosplit', 'alsonosplit'])
        result = s.str.rsplit('_', expand=True)
        exp = DataFrame({0: Series(['nosplit', 'alsonosplit'])})
        tm.assert_frame_equal(result, exp)

        s = Series(['some_equal_splits', 'with_no_nans'])
        result = s.str.rsplit('_', expand=True)
        exp = DataFrame({0: ['some', 'with'],
                         1: ['equal', 'no'],
                         2: ['splits', 'nans']})
        tm.assert_frame_equal(result, exp)

        result = s.str.rsplit('_', expand=True, n=2)
        exp = DataFrame({0: ['some', 'with'],
                         1: ['equal', 'no'],
                         2: ['splits', 'nans']})
        tm.assert_frame_equal(result, exp)

        result = s.str.rsplit('_', expand=True, n=1)
        exp = DataFrame({0: ['some_equal', 'with_no'], 1: ['splits', 'nans']})
        tm.assert_frame_equal(result, exp)

        s = Series(['some_splits', 'with_index'], index=['preserve', 'me'])
        result = s.str.rsplit('_', expand=True)
        exp = DataFrame({0: ['some', 'with'], 1: ['splits', 'index']},
                        index=['preserve', 'me'])
        tm.assert_frame_equal(result, exp)

    def test_rsplit_to_multiindex_expand(self):
        idx = Index(['nosplit', 'alsonosplit'])
        result = idx.str.rsplit('_', expand=True)
        exp = idx
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 1

        idx = Index(['some_equal_splits', 'with_no_nans'])
        result = idx.str.rsplit('_', expand=True)
        exp = MultiIndex.from_tuples([('some', 'equal', 'splits'), (
            'with', 'no', 'nans')])
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 3

        idx = Index(['some_equal_splits', 'with_no_nans'])
        result = idx.str.rsplit('_', expand=True, n=1)
        exp = MultiIndex.from_tuples([('some_equal', 'splits'),
                                      ('with_no', 'nans')])
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 2

    def test_split_nan_expand(self):
        # gh-18450
        s = Series(["foo,bar,baz", NA])
        result = s.str.split(",", expand=True)
        exp = DataFrame([["foo", "bar", "baz"], [NA, NA, NA]])
        tm.assert_frame_equal(result, exp)

        # check that these are actually np.nan and not None
        # TODO see GH 18463
        # tm.assert_frame_equal does not differentiate
        assert all(np.isnan(x) for x in result.iloc[1])

    def test_split_with_name(self):
        # GH 12617

        # should preserve name
        s = Series(['a,b', 'c,d'], name='xxx')
        res = s.str.split(',')
        exp = Series([['a', 'b'], ['c', 'd']], name='xxx')
        tm.assert_series_equal(res, exp)

        res = s.str.split(',', expand=True)
        exp = DataFrame([['a', 'b'], ['c', 'd']])
        tm.assert_frame_equal(res, exp)

        idx = Index(['a,b', 'c,d'], name='xxx')
        res = idx.str.split(',')
        exp = Index([['a', 'b'], ['c', 'd']], name='xxx')
        assert res.nlevels == 1
        tm.assert_index_equal(res, exp)

        res = idx.str.split(',', expand=True)
        exp = MultiIndex.from_tuples([('a', 'b'), ('c', 'd')])
        assert res.nlevels == 2
        tm.assert_index_equal(res, exp)

    def test_partition_series(self):
        # https://github.com/pandas-dev/pandas/issues/23558

        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h', None])

        result = values.str.partition('_', expand=False)
        exp = Series([('a', '_', 'b_c'), ('c', '_', 'd_e'), NA,
                      ('f', '_', 'g_h'), None])
        tm.assert_series_equal(result, exp)

        result = values.str.rpartition('_', expand=False)
        exp = Series([('a_b', '_', 'c'), ('c_d', '_', 'e'), NA,
                      ('f_g', '_', 'h'), None])
        tm.assert_series_equal(result, exp)

        # more than one char
        values = Series(['a__b__c', 'c__d__e', NA, 'f__g__h', None])
        result = values.str.partition('__', expand=False)
        exp = Series([('a', '__', 'b__c'), ('c', '__', 'd__e'), NA,
                      ('f', '__', 'g__h'), None])
        tm.assert_series_equal(result, exp)

        result = values.str.rpartition('__', expand=False)
        exp = Series([('a__b', '__', 'c'), ('c__d', '__', 'e'), NA,
                      ('f__g', '__', 'h'), None])
        tm.assert_series_equal(result, exp)

        # None
        values = Series(['a b c', 'c d e', NA, 'f g h', None])
        result = values.str.partition(expand=False)
        exp = Series([('a', ' ', 'b c'), ('c', ' ', 'd e'), NA,
                      ('f', ' ', 'g h'), None])
        tm.assert_series_equal(result, exp)

        result = values.str.rpartition(expand=False)
        exp = Series([('a b', ' ', 'c'), ('c d', ' ', 'e'), NA,
                      ('f g', ' ', 'h'), None])
        tm.assert_series_equal(result, exp)

        # Not split
        values = Series(['abc', 'cde', NA, 'fgh', None])
        result = values.str.partition('_', expand=False)
        exp = Series([('abc', '', ''), ('cde', '', ''), NA,
                      ('fgh', '', ''), None])
        tm.assert_series_equal(result, exp)

        result = values.str.rpartition('_', expand=False)
        exp = Series([('', '', 'abc'), ('', '', 'cde'), NA,
                      ('', '', 'fgh'), None])
        tm.assert_series_equal(result, exp)

        # unicode
        values = Series([u'a_b_c', u'c_d_e', NA, u'f_g_h'])

        result = values.str.partition('_', expand=False)
        exp = Series([(u'a', u'_', u'b_c'), (u'c', u'_', u'd_e'),
                      NA, (u'f', u'_', u'g_h')])
        tm.assert_series_equal(result, exp)

        result = values.str.rpartition('_', expand=False)
        exp = Series([(u'a_b', u'_', u'c'), (u'c_d', u'_', u'e'),
                      NA, (u'f_g', u'_', u'h')])
        tm.assert_series_equal(result, exp)

        # compare to standard lib
        values = Series(['A_B_C', 'B_C_D', 'E_F_G', 'EFGHEF'])
        result = values.str.partition('_', expand=False).tolist()
        assert result == [v.partition('_') for v in values]
        result = values.str.rpartition('_', expand=False).tolist()
        assert result == [v.rpartition('_') for v in values]

    def test_partition_index(self):
        # https://github.com/pandas-dev/pandas/issues/23558

        values = Index(['a_b_c', 'c_d_e', 'f_g_h', np.nan, None])

        result = values.str.partition('_', expand=False)
        exp = Index(np.array([('a', '_', 'b_c'), ('c', '_', 'd_e'),
                              ('f', '_', 'g_h'), np.nan, None]))
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 1

        result = values.str.rpartition('_', expand=False)
        exp = Index(np.array([('a_b', '_', 'c'), ('c_d', '_', 'e'),
                              ('f_g', '_', 'h'), np.nan, None]))
        tm.assert_index_equal(result, exp)
        assert result.nlevels == 1

        result = values.str.partition('_')
        exp = Index([('a', '_', 'b_c'), ('c', '_', 'd_e'),
                     ('f', '_', 'g_h'), (np.nan, np.nan, np.nan),
                     (None, None, None)])
        tm.assert_index_equal(result, exp)
        assert isinstance(result, MultiIndex)
        assert result.nlevels == 3

        result = values.str.rpartition('_')
        exp = Index([('a_b', '_', 'c'), ('c_d', '_', 'e'),
                     ('f_g', '_', 'h'), (np.nan, np.nan, np.nan),
                     (None, None, None)])
        tm.assert_index_equal(result, exp)
        assert isinstance(result, MultiIndex)
        assert result.nlevels == 3

    def test_partition_to_dataframe(self):
        # https://github.com/pandas-dev/pandas/issues/23558

        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h', None])
        result = values.str.partition('_')
        exp = DataFrame({0: ['a', 'c', np.nan, 'f', None],
                         1: ['_', '_', np.nan, '_', None],
                         2: ['b_c', 'd_e', np.nan, 'g_h', None]})
        tm.assert_frame_equal(result, exp)

        result = values.str.rpartition('_')
        exp = DataFrame({0: ['a_b', 'c_d', np.nan, 'f_g', None],
                         1: ['_', '_', np.nan, '_', None],
                         2: ['c', 'e', np.nan, 'h', None]})
        tm.assert_frame_equal(result, exp)

        values = Series(['a_b_c', 'c_d_e', NA, 'f_g_h', None])
        result = values.str.partition('_', expand=True)
        exp = DataFrame({0: ['a', 'c', np.nan, 'f', None],
                         1: ['_', '_', np.nan, '_', None],
                         2: ['b_c', 'd_e', np.nan, 'g_h', None]})
        tm.assert_frame_equal(result, exp)

        result = values.str.rpartition('_', expand=True)
        exp = DataFrame({0: ['a_b', 'c_d', np.nan, 'f_g', None],
                         1: ['_', '_', np.nan, '_', None],
                         2: ['c', 'e', np.nan, 'h', None]})
        tm.assert_frame_equal(result, exp)

    def test_partition_with_name(self):
        # GH 12617

        s = Series(['a,b', 'c,d'], name='xxx')
        res = s.str.partition(',')
        exp = DataFrame({0: ['a', 'c'], 1: [',', ','], 2: ['b', 'd']})
        tm.assert_frame_equal(res, exp)

        # should preserve name
        res = s.str.partition(',', expand=False)
        exp = Series([('a', ',', 'b'), ('c', ',', 'd')], name='xxx')
        tm.assert_series_equal(res, exp)

        idx = Index(['a,b', 'c,d'], name='xxx')
        res = idx.str.partition(',')
        exp = MultiIndex.from_tuples([('a', ',', 'b'), ('c', ',', 'd')])
        assert res.nlevels == 3
        tm.assert_index_equal(res, exp)

        # should preserve name
        res = idx.str.partition(',', expand=False)
        exp = Index(np.array([('a', ',', 'b'), ('c', ',', 'd')]), name='xxx')
        assert res.nlevels == 1
        tm.assert_index_equal(res, exp)

    def test_pipe_failures(self):
        # #2119
        s = Series(['A|B|C'])

        result = s.str.split('|')
        exp = Series([['A', 'B', 'C']])

        tm.assert_series_equal(result, exp)

        result = s.str.replace('|', ' ')
        exp = Series(['A B C'])

        tm.assert_series_equal(result, exp)

    def test_slice(self):
        values = Series(['aafootwo', 'aabartwo', NA, 'aabazqux'])

        result = values.str.slice(2, 5)
        exp = Series(['foo', 'bar', NA, 'baz'])
        tm.assert_series_equal(result, exp)

        for start, stop, step in [(0, 3, -1), (None, None, -1), (3, 10, 2),
                                  (3, 0, -1)]:
            try:
                result = values.str.slice(start, stop, step)
                expected = Series([s[start:stop:step] if not isna(s) else NA
                                   for s in values])
                tm.assert_series_equal(result, expected)
            except:
                print('failed on %s:%s:%s' % (start, stop, step))
                raise

        # mixed
        mixed = Series(['aafootwo', NA, 'aabartwo', True, datetime.today(),
                        None, 1, 2.])

        rs = Series(mixed).str.slice(2, 5)
        xp = Series(['foo', NA, 'bar', NA, NA, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        rs = Series(mixed).str.slice(2, 5, -1)
        xp = Series(['oof', NA, 'rab', NA, NA, NA, NA, NA])

        # unicode
        values = Series([u('aafootwo'), u('aabartwo'), NA, u('aabazqux')])

        result = values.str.slice(2, 5)
        exp = Series([u('foo'), u('bar'), NA, u('baz')])
        tm.assert_series_equal(result, exp)

        result = values.str.slice(0, -1, 2)
        exp = Series([u('afow'), u('abrw'), NA, u('abzu')])
        tm.assert_series_equal(result, exp)

    def test_slice_replace(self):
        values = Series(['short', 'a bit longer', 'evenlongerthanthat', '', NA
                         ])

        exp = Series(['shrt', 'a it longer', 'evnlongerthanthat', '', NA])
        result = values.str.slice_replace(2, 3)
        tm.assert_series_equal(result, exp)

        exp = Series(['shzrt', 'a zit longer', 'evznlongerthanthat', 'z', NA])
        result = values.str.slice_replace(2, 3, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['shzort', 'a zbit longer', 'evzenlongerthanthat', 'z', NA
                      ])
        result = values.str.slice_replace(2, 2, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['shzort', 'a zbit longer', 'evzenlongerthanthat', 'z', NA
                      ])
        result = values.str.slice_replace(2, 1, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['shorz', 'a bit longez', 'evenlongerthanthaz', 'z', NA])
        result = values.str.slice_replace(-1, None, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['zrt', 'zer', 'zat', 'z', NA])
        result = values.str.slice_replace(None, -2, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['shortz', 'a bit znger', 'evenlozerthanthat', 'z', NA])
        result = values.str.slice_replace(6, 8, 'z')
        tm.assert_series_equal(result, exp)

        exp = Series(['zrt', 'a zit longer', 'evenlongzerthanthat', 'z', NA])
        result = values.str.slice_replace(-10, 3, 'z')
        tm.assert_series_equal(result, exp)

    def test_strip_lstrip_rstrip(self):
        values = Series(['  aa   ', ' bb \n', NA, 'cc  '])

        result = values.str.strip()
        exp = Series(['aa', 'bb', NA, 'cc'])
        tm.assert_series_equal(result, exp)

        result = values.str.lstrip()
        exp = Series(['aa   ', 'bb \n', NA, 'cc  '])
        tm.assert_series_equal(result, exp)

        result = values.str.rstrip()
        exp = Series(['  aa', ' bb', NA, 'cc'])
        tm.assert_series_equal(result, exp)

    def test_strip_lstrip_rstrip_mixed(self):
        # mixed
        mixed = Series(['  aa  ', NA, ' bb \t\n', True, datetime.today(), None,
                        1, 2.])

        rs = Series(mixed).str.strip()
        xp = Series(['aa', NA, 'bb', NA, NA, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        rs = Series(mixed).str.lstrip()
        xp = Series(['aa  ', NA, 'bb \t\n', NA, NA, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        rs = Series(mixed).str.rstrip()
        xp = Series(['  aa', NA, ' bb', NA, NA, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

    def test_strip_lstrip_rstrip_unicode(self):
        # unicode
        values = Series([u('  aa   '), u(' bb \n'), NA, u('cc  ')])

        result = values.str.strip()
        exp = Series([u('aa'), u('bb'), NA, u('cc')])
        tm.assert_series_equal(result, exp)

        result = values.str.lstrip()
        exp = Series([u('aa   '), u('bb \n'), NA, u('cc  ')])
        tm.assert_series_equal(result, exp)

        result = values.str.rstrip()
        exp = Series([u('  aa'), u(' bb'), NA, u('cc')])
        tm.assert_series_equal(result, exp)

    def test_strip_lstrip_rstrip_args(self):
        values = Series(['xxABCxx', 'xx BNSD', 'LDFJH xx'])

        rs = values.str.strip('x')
        xp = Series(['ABC', ' BNSD', 'LDFJH '])
        assert_series_equal(rs, xp)

        rs = values.str.lstrip('x')
        xp = Series(['ABCxx', ' BNSD', 'LDFJH xx'])
        assert_series_equal(rs, xp)

        rs = values.str.rstrip('x')
        xp = Series(['xxABC', 'xx BNSD', 'LDFJH '])
        assert_series_equal(rs, xp)

    def test_strip_lstrip_rstrip_args_unicode(self):
        values = Series([u('xxABCxx'), u('xx BNSD'), u('LDFJH xx')])

        rs = values.str.strip(u('x'))
        xp = Series(['ABC', ' BNSD', 'LDFJH '])
        assert_series_equal(rs, xp)

        rs = values.str.lstrip(u('x'))
        xp = Series(['ABCxx', ' BNSD', 'LDFJH xx'])
        assert_series_equal(rs, xp)

        rs = values.str.rstrip(u('x'))
        xp = Series(['xxABC', 'xx BNSD', 'LDFJH '])
        assert_series_equal(rs, xp)

    def test_wrap(self):
        # test values are: two words less than width, two words equal to width,
        # two words greater than width, one word less than width, one word
        # equal to width, one word greater than width, multiple tokens with
        # trailing whitespace equal to width
        values = Series([u('hello world'), u('hello world!'), u(
            'hello world!!'), u('abcdefabcde'), u('abcdefabcdef'), u(
                'abcdefabcdefa'), u('ab ab ab ab '), u('ab ab ab ab a'), u(
                    '\t')])

        # expected values
        xp = Series([u('hello world'), u('hello world!'), u('hello\nworld!!'),
                     u('abcdefabcde'), u('abcdefabcdef'), u('abcdefabcdef\na'),
                     u('ab ab ab ab'), u('ab ab ab ab\na'), u('')])

        rs = values.str.wrap(12, break_long_words=True)
        assert_series_equal(rs, xp)

        # test with pre and post whitespace (non-unicode), NaN, and non-ascii
        # Unicode
        values = Series(['  pre  ', np.nan, u('\xac\u20ac\U00008000 abadcafe')
                         ])
        xp = Series(['  pre', NA, u('\xac\u20ac\U00008000 ab\nadcafe')])
        rs = values.str.wrap(6)
        assert_series_equal(rs, xp)

    def test_get(self):
        values = Series(['a_b_c', 'c_d_e', np.nan, 'f_g_h'])

        result = values.str.split('_').str.get(1)
        expected = Series(['b', 'd', np.nan, 'g'])
        tm.assert_series_equal(result, expected)

        # mixed
        mixed = Series(['a_b_c', NA, 'c_d_e', True, datetime.today(), None, 1,
                        2.])

        rs = Series(mixed).str.split('_').str.get(1)
        xp = Series(['b', NA, 'd', NA, NA, NA, NA, NA])

        assert isinstance(rs, Series)
        tm.assert_almost_equal(rs, xp)

        # unicode
        values = Series([u('a_b_c'), u('c_d_e'), np.nan, u('f_g_h')])

        result = values.str.split('_').str.get(1)
        expected = Series([u('b'), u('d'), np.nan, u('g')])
        tm.assert_series_equal(result, expected)

        # bounds testing
        values = Series(['1_2_3_4_5', '6_7_8_9_10', '11_12'])

        # positive index
        result = values.str.split('_').str.get(2)
        expected = Series(['3', '8', np.nan])
        tm.assert_series_equal(result, expected)

        # negative index
        result = values.str.split('_').str.get(-3)
        expected = Series(['3', '8', np.nan])
        tm.assert_series_equal(result, expected)

    def test_get_complex(self):
        # GH 20671, getting value not in dict raising `KeyError`
        values = Series([(1, 2, 3), [1, 2, 3], {1, 2, 3},
                         {1: 'a', 2: 'b', 3: 'c'}])

        result = values.str.get(1)
        expected = Series([2, 2, np.nan, 'a'])
        tm.assert_series_equal(result, expected)

        result = values.str.get(-1)
        expected = Series([3, 3, np.nan, np.nan])
        tm.assert_series_equal(result, expected)

    @pytest.mark.parametrize('to_type', [tuple, list, np.array])
    def test_get_complex_nested(self, to_type):
        values = Series([to_type([to_type([1, 2])])])

        result = values.str.get(0)
        expected = Series([to_type([1, 2])])
        tm.assert_series_equal(result, expected)

        result = values.str.get(1)
        expected = Series([np.nan])
        tm.assert_series_equal(result, expected)

    def test_more_contains(self):
        # PR #1179
        s = Series(['A', 'B', 'C', 'Aaba', 'Baca', '', NA,
                    'CABA', 'dog', 'cat'])

        result = s.str.contains('a')
        expected = Series([False, False, False, True, True, False, np.nan,
                           False, False, True])
        assert_series_equal(result, expected)

        result = s.str.contains('a', case=False)
        expected = Series([True, False, False, True, True, False, np.nan, True,
                           False, True])
        assert_series_equal(result, expected)

        result = s.str.contains('Aa')
        expected = Series([False, False, False, True, False, False, np.nan,
                           False, False, False])
        assert_series_equal(result, expected)

        result = s.str.contains('ba')
        expected = Series([False, False, False, True, False, False, np.nan,
                           False, False, False])
        assert_series_equal(result, expected)

        result = s.str.contains('ba', case=False)
        expected = Series([False, False, False, True, True, False, np.nan,
                           True, False, False])
        assert_series_equal(result, expected)

    def test_contains_nan(self):
        # PR #14171
        s = Series([np.nan, np.nan, np.nan], dtype=np.object_)

        result = s.str.contains('foo', na=False)
        expected = Series([False, False, False], dtype=np.bool_)
        assert_series_equal(result, expected)

        result = s.str.contains('foo', na=True)
        expected = Series([True, True, True], dtype=np.bool_)
        assert_series_equal(result, expected)

        result = s.str.contains('foo', na="foo")
        expected = Series(["foo", "foo", "foo"], dtype=np.object_)
        assert_series_equal(result, expected)

        result = s.str.contains('foo')
        expected = Series([np.nan, np.nan, np.nan], dtype=np.object_)
        assert_series_equal(result, expected)

    def test_more_replace(self):
        # PR #1179
        s = Series(['A', 'B', 'C', 'Aaba', 'Baca', '', NA, 'CABA',
                    'dog', 'cat'])

        result = s.str.replace('A', 'YYY')
        expected = Series(['YYY', 'B', 'C', 'YYYaba', 'Baca', '', NA,
                           'CYYYBYYY', 'dog', 'cat'])
        assert_series_equal(result, expected)

        result = s.str.replace('A', 'YYY', case=False)
        expected = Series(['YYY', 'B', 'C', 'YYYYYYbYYY', 'BYYYcYYY', '', NA,
                           'CYYYBYYY', 'dog', 'cYYYt'])
        assert_series_equal(result, expected)

        result = s.str.replace('^.a|dog', 'XX-XX ', case=False)
        expected = Series(['A', 'B', 'C', 'XX-XX ba', 'XX-XX ca', '', NA,
                           'XX-XX BA', 'XX-XX ', 'XX-XX t'])
        assert_series_equal(result, expected)

    def test_string_slice_get_syntax(self):
        s = Series(['YYY', 'B', 'C', 'YYYYYYbYYY', 'BYYYcYYY', NA, 'CYYYBYYY',
                    'dog', 'cYYYt'])

        result = s.str[0]
        expected = s.str.get(0)
        assert_series_equal(result, expected)

        result = s.str[:3]
        expected = s.str.slice(stop=3)
        assert_series_equal(result, expected)

        result = s.str[2::-1]
        expected = s.str.slice(start=2, step=-1)
        assert_series_equal(result, expected)

    def test_string_slice_out_of_bounds(self):
        s = Series([(1, 2), (1, ), (3, 4, 5)])

        result = s.str[1]
        expected = Series([2, np.nan, 4])

        assert_series_equal(result, expected)

        s = Series(['foo', 'b', 'ba'])
        result = s.str[1]
        expected = Series(['o', np.nan, 'a'])
        assert_series_equal(result, expected)

    def test_match_findall_flags(self):
        data = {'Dave': 'dave@google.com',
                'Steve': 'steve@gmail.com',
                'Rob': 'rob@gmail.com',
                'Wes': np.nan}
        data = Series(data)

        pat = r'([A-Z0-9._%+-]+)@([A-Z0-9.-]+)\.([A-Z]{2,4})'

        result = data.str.extract(pat, flags=re.IGNORECASE, expand=True)
        assert result.iloc[0].tolist() == ['dave', 'google', 'com']

        result = data.str.match(pat, flags=re.IGNORECASE)
        assert result[0]

        result = data.str.findall(pat, flags=re.IGNORECASE)
        assert result[0][0] == ('dave', 'google', 'com')

        result = data.str.count(pat, flags=re.IGNORECASE)
        assert result[0] == 1

        with tm.assert_produces_warning(UserWarning):
            result = data.str.contains(pat, flags=re.IGNORECASE)
        assert result[0]

    def test_encode_decode(self):
        base = Series([u('a'), u('b'), u('a\xe4')])
        series = base.str.encode('utf-8')

        f = lambda x: x.decode('utf-8')
        result = series.str.decode('utf-8')
        exp = series.map(f)

        tm.assert_series_equal(result, exp)

    def test_encode_decode_errors(self):
        encodeBase = Series([u('a'), u('b'), u('a\x9d')])

        pytest.raises(UnicodeEncodeError, encodeBase.str.encode, 'cp1252')

        f = lambda x: x.encode('cp1252', 'ignore')
        result = encodeBase.str.encode('cp1252', 'ignore')
        exp = encodeBase.map(f)
        tm.assert_series_equal(result, exp)

        decodeBase = Series([b'a', b'b', b'a\x9d'])

        pytest.raises(UnicodeDecodeError, decodeBase.str.decode, 'cp1252')

        f = lambda x: x.decode('cp1252', 'ignore')
        result = decodeBase.str.decode('cp1252', 'ignore')
        exp = decodeBase.map(f)

        tm.assert_series_equal(result, exp)

    def test_normalize(self):
        values = ['ABC', u'ＡＢＣ', u'１２３', np.nan, u'ｱｲｴ']
        s = Series(values, index=['a', 'b', 'c', 'd', 'e'])

        normed = [u'ABC', u'ABC', u'123', np.nan, u'アイエ']
        expected = Series(normed, index=['a', 'b', 'c', 'd', 'e'])

        result = s.str.normalize('NFKC')
        tm.assert_series_equal(result, expected)

        expected = Series([u'ABC', u'ＡＢＣ', u'１２３', np.nan, u'ｱｲｴ'],
                          index=['a', 'b', 'c', 'd', 'e'])

        result = s.str.normalize('NFC')
        tm.assert_series_equal(result, expected)

        with pytest.raises(ValueError, match="invalid normalization form"):
            s.str.normalize('xxx')

        s = Index([u'ＡＢＣ', u'１２３', u'ｱｲｴ'])
        expected = Index([u'ABC', u'123', u'アイエ'])
        result = s.str.normalize('NFKC')
        tm.assert_index_equal(result, expected)

    def test_index_str_accessor_visibility(self):
        from pandas.core.strings import StringMethods

        if not compat.PY3:
            cases = [(['a', 'b'], 'string'), (['a', u('b')], 'mixed'),
                     ([u('a'), u('b')], 'unicode'),
                     (['a', 'b', 1], 'mixed-integer'),
                     (['a', 'b', 1.3], 'mixed'),
                     (['a', 'b', 1.3, 1], 'mixed-integer'),
                     (['aa', datetime(2011, 1, 1)], 'mixed')]
        else:
            cases = [(['a', 'b'], 'string'), (['a', u('b')], 'string'),
                     ([u('a'), u('b')], 'string'),
                     (['a', 'b', 1], 'mixed-integer'),
                     (['a', 'b', 1.3], 'mixed'),
                     (['a', 'b', 1.3, 1], 'mixed-integer'),
                     (['aa', datetime(2011, 1, 1)], 'mixed')]
        for values, tp in cases:
            idx = Index(values)
            assert isinstance(Series(values).str, StringMethods)
            assert isinstance(idx.str, StringMethods)
            assert idx.inferred_type == tp

        for values, tp in cases:
            idx = Index(values)
            assert isinstance(Series(values).str, StringMethods)
            assert isinstance(idx.str, StringMethods)
            assert idx.inferred_type == tp

        cases = [([1, np.nan], 'floating'),
                 ([datetime(2011, 1, 1)], 'datetime64'),
                 ([timedelta(1)], 'timedelta64')]
        for values, tp in cases:
            idx = Index(values)
            message = 'Can only use .str accessor with string values'
            with pytest.raises(AttributeError, match=message):
                Series(values).str
            with pytest.raises(AttributeError, match=message):
                idx.str
            assert idx.inferred_type == tp

        # MultiIndex has mixed dtype, but not allow to use accessor
        idx = MultiIndex.from_tuples([('a', 'b'), ('a', 'b')])
        assert idx.inferred_type == 'mixed'
        message = 'Can only use .str accessor with Index, not MultiIndex'
        with pytest.raises(AttributeError, match=message):
            idx.str

    def test_str_accessor_no_new_attributes(self):
        # https://github.com/pandas-dev/pandas/issues/10673
        s = Series(list('aabbcde'))
        with pytest.raises(AttributeError,
                           match="You cannot add any new attribute"):
            s.str.xlabel = "a"

    def test_method_on_bytes(self):
        lhs = Series(np.array(list('abc'), 'S1').astype(object))
        rhs = Series(np.array(list('def'), 'S1').astype(object))
        if compat.PY3:
            pytest.raises(TypeError, lhs.str.cat, rhs)
        else:
            result = lhs.str.cat(rhs)
            expected = Series(np.array(
                ['ad', 'be', 'cf'], 'S2').astype(object))
            tm.assert_series_equal(result, expected)