test_operators.py

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

from datetime import datetime, timedelta
import operator
from itertools import product, starmap

from numpy import nan, inf
import numpy as np
import pandas as pd

from pandas import (Index, Series, DataFrame, isnull, bdate_range,
                    NaT, date_range, timedelta_range,
                    _np_version_under1p8)
from pandas.tseries.index import Timestamp
from pandas.tseries.tdi import Timedelta
import pandas.core.nanops as nanops

from pandas.compat import range, zip
from pandas import compat
from pandas.util.testing import assert_series_equal, assert_almost_equal
import pandas.util.testing as tm

from .common import TestData


class TestSeriesOperators(TestData, tm.TestCase):

    _multiprocess_can_split_ = True

    def test_comparisons(self):
        left = np.random.randn(10)
        right = np.random.randn(10)
        left[:3] = np.nan

        result = nanops.nangt(left, right)
        expected = (left > right).astype('O')
        expected[:3] = np.nan

        assert_almost_equal(result, expected)

        s = Series(['a', 'b', 'c'])
        s2 = Series([False, True, False])

        # it works!
        s == s2
        s2 == s

    def test_op_method(self):
        def check(series, other, check_reverse=False):
            simple_ops = ['add', 'sub', 'mul', 'floordiv', 'truediv', 'pow']
            if not compat.PY3:
                simple_ops.append('div')

            for opname in simple_ops:
                op = getattr(Series, opname)

                if op == 'div':
                    alt = operator.truediv
                else:
                    alt = getattr(operator, opname)

                result = op(series, other)
                expected = alt(series, other)
                tm.assert_almost_equal(result, expected)
                if check_reverse:
                    rop = getattr(Series, "r" + opname)
                    result = rop(series, other)
                    expected = alt(other, series)
                    tm.assert_almost_equal(result, expected)

        check(self.ts, self.ts * 2)
        check(self.ts, self.ts[::2])
        check(self.ts, 5, check_reverse=True)
        check(tm.makeFloatSeries(), tm.makeFloatSeries(), check_reverse=True)

    def test_neg(self):
        assert_series_equal(-self.series, -1 * self.series)

    def test_invert(self):
        assert_series_equal(-(self.series < 0), ~(self.series < 0))

    def test_div(self):

        # no longer do integer div for any ops, but deal with the 0's
        p = DataFrame({'first': [3, 4, 5, 8], 'second': [0, 0, 0, 3]})
        result = p['first'] / p['second']
        expected = Series(p['first'].values.astype(float) / p['second'].values,
                          dtype='float64')
        expected.iloc[0:3] = np.inf
        assert_series_equal(result, expected)

        result = p['first'] / 0
        expected = Series(np.inf, index=p.index, name='first')
        assert_series_equal(result, expected)

        p = p.astype('float64')
        result = p['first'] / p['second']
        expected = Series(p['first'].values / p['second'].values)
        assert_series_equal(result, expected)

        p = DataFrame({'first': [3, 4, 5, 8], 'second': [1, 1, 1, 1]})
        result = p['first'] / p['second']
        assert_series_equal(result, p['first'].astype('float64'),
                            check_names=False)
        self.assertTrue(result.name is None)
        self.assertFalse(np.array_equal(result, p['second'] / p['first']))

        # inf signing
        s = Series([np.nan, 1., -1.])
        result = s / 0
        expected = Series([np.nan, np.inf, -np.inf])
        assert_series_equal(result, expected)

        # float/integer issue
        # GH 7785
        p = DataFrame({'first': (1, 0), 'second': (-0.01, -0.02)})
        expected = Series([-0.01, -np.inf])

        result = p['second'].div(p['first'])
        assert_series_equal(result, expected, check_names=False)

        result = p['second'] / p['first']
        assert_series_equal(result, expected)

        # GH 9144
        s = Series([-1, 0, 1])

        result = 0 / s
        expected = Series([0.0, nan, 0.0])
        assert_series_equal(result, expected)

        result = s / 0
        expected = Series([-inf, nan, inf])
        assert_series_equal(result, expected)

        result = s // 0
        expected = Series([-inf, nan, inf])
        assert_series_equal(result, expected)

    def test_operators(self):
        def _check_op(series, other, op, pos_only=False):
            left = np.abs(series) if pos_only else series
            right = np.abs(other) if pos_only else other

            cython_or_numpy = op(left, right)
            python = left.combine(right, op)
            tm.assert_almost_equal(cython_or_numpy, python)

        def check(series, other):
            simple_ops = ['add', 'sub', 'mul', 'truediv', 'floordiv', 'mod']

            for opname in simple_ops:
                _check_op(series, other, getattr(operator, opname))

            _check_op(series, other, operator.pow, pos_only=True)

            _check_op(series, other, lambda x, y: operator.add(y, x))
            _check_op(series, other, lambda x, y: operator.sub(y, x))
            _check_op(series, other, lambda x, y: operator.truediv(y, x))
            _check_op(series, other, lambda x, y: operator.floordiv(y, x))
            _check_op(series, other, lambda x, y: operator.mul(y, x))
            _check_op(series, other, lambda x, y: operator.pow(y, x),
                      pos_only=True)
            _check_op(series, other, lambda x, y: operator.mod(y, x))

        check(self.ts, self.ts * 2)
        check(self.ts, self.ts * 0)
        check(self.ts, self.ts[::2])
        check(self.ts, 5)

        def check_comparators(series, other):
            _check_op(series, other, operator.gt)
            _check_op(series, other, operator.ge)
            _check_op(series, other, operator.eq)
            _check_op(series, other, operator.lt)
            _check_op(series, other, operator.le)

        check_comparators(self.ts, 5)
        check_comparators(self.ts, self.ts + 1)

    def test_operators_empty_int_corner(self):
        s1 = Series([], [], dtype=np.int32)
        s2 = Series({'x': 0.})
        tm.assert_series_equal(s1 * s2, Series([np.nan], index=['x']))

    def test_operators_timedelta64(self):

        # invalid ops
        self.assertRaises(Exception, self.objSeries.__add__, 1)
        self.assertRaises(Exception, self.objSeries.__add__,
                          np.array(1, dtype=np.int64))
        self.assertRaises(Exception, self.objSeries.__sub__, 1)
        self.assertRaises(Exception, self.objSeries.__sub__,
                          np.array(1, dtype=np.int64))

        # seriese ops
        v1 = date_range('2012-1-1', periods=3, freq='D')
        v2 = date_range('2012-1-2', periods=3, freq='D')
        rs = Series(v2) - Series(v1)
        xp = Series(1e9 * 3600 * 24,
                    rs.index).astype('int64').astype('timedelta64[ns]')
        assert_series_equal(rs, xp)
        self.assertEqual(rs.dtype, 'timedelta64[ns]')

        df = DataFrame(dict(A=v1))
        td = Series([timedelta(days=i) for i in range(3)])
        self.assertEqual(td.dtype, 'timedelta64[ns]')

        # series on the rhs
        result = df['A'] - df['A'].shift()
        self.assertEqual(result.dtype, 'timedelta64[ns]')

        result = df['A'] + td
        self.assertEqual(result.dtype, 'M8[ns]')

        # scalar Timestamp on rhs
        maxa = df['A'].max()
        tm.assertIsInstance(maxa, Timestamp)

        resultb = df['A'] - df['A'].max()
        self.assertEqual(resultb.dtype, 'timedelta64[ns]')

        # timestamp on lhs
        result = resultb + df['A']
        values = [Timestamp('20111230'), Timestamp('20120101'),
                  Timestamp('20120103')]
        expected = Series(values, name='A')
        assert_series_equal(result, expected)

        # datetimes on rhs
        result = df['A'] - datetime(2001, 1, 1)
        expected = Series(
            [timedelta(days=4017 + i) for i in range(3)], name='A')
        assert_series_equal(result, expected)
        self.assertEqual(result.dtype, 'm8[ns]')

        d = datetime(2001, 1, 1, 3, 4)
        resulta = df['A'] - d
        self.assertEqual(resulta.dtype, 'm8[ns]')

        # roundtrip
        resultb = resulta + d
        assert_series_equal(df['A'], resultb)

        # timedeltas on rhs
        td = timedelta(days=1)
        resulta = df['A'] + td
        resultb = resulta - td
        assert_series_equal(resultb, df['A'])
        self.assertEqual(resultb.dtype, 'M8[ns]')

        # roundtrip
        td = timedelta(minutes=5, seconds=3)
        resulta = df['A'] + td
        resultb = resulta - td
        assert_series_equal(df['A'], resultb)
        self.assertEqual(resultb.dtype, 'M8[ns]')

        # inplace
        value = rs[2] + np.timedelta64(timedelta(minutes=5, seconds=1))
        rs[2] += np.timedelta64(timedelta(minutes=5, seconds=1))
        self.assertEqual(rs[2], value)

    def test_timedeltas_with_DateOffset(self):

        # GH 4532
        # operate with pd.offsets
        s = Series([Timestamp('20130101 9:01'), Timestamp('20130101 9:02')])

        result = s + pd.offsets.Second(5)
        result2 = pd.offsets.Second(5) + s
        expected = Series([Timestamp('20130101 9:01:05'), Timestamp(
            '20130101 9:02:05')])
        assert_series_equal(result, expected)
        assert_series_equal(result2, expected)

        result = s - pd.offsets.Second(5)
        result2 = -pd.offsets.Second(5) + s
        expected = Series([Timestamp('20130101 9:00:55'), Timestamp(
            '20130101 9:01:55')])
        assert_series_equal(result, expected)
        assert_series_equal(result2, expected)

        result = s + pd.offsets.Milli(5)
        result2 = pd.offsets.Milli(5) + s
        expected = Series([Timestamp('20130101 9:01:00.005'), Timestamp(
            '20130101 9:02:00.005')])
        assert_series_equal(result, expected)
        assert_series_equal(result2, expected)

        result = s + pd.offsets.Minute(5) + pd.offsets.Milli(5)
        expected = Series([Timestamp('20130101 9:06:00.005'), Timestamp(
            '20130101 9:07:00.005')])
        assert_series_equal(result, expected)

        # operate with np.timedelta64 correctly
        result = s + np.timedelta64(1, 's')
        result2 = np.timedelta64(1, 's') + s
        expected = Series([Timestamp('20130101 9:01:01'), Timestamp(
            '20130101 9:02:01')])
        assert_series_equal(result, expected)
        assert_series_equal(result2, expected)

        result = s + np.timedelta64(5, 'ms')
        result2 = np.timedelta64(5, 'ms') + s
        expected = Series([Timestamp('20130101 9:01:00.005'), Timestamp(
            '20130101 9:02:00.005')])
        assert_series_equal(result, expected)
        assert_series_equal(result2, expected)

        # valid DateOffsets
        for do in ['Hour', 'Minute', 'Second', 'Day', 'Micro', 'Milli',
                   'Nano']:
            op = getattr(pd.offsets, do)
            s + op(5)
            op(5) + s

    def test_timedelta_series_ops(self):
        # GH11925

        s = Series(timedelta_range('1 day', periods=3))
        ts = Timestamp('2012-01-01')
        expected = Series(date_range('2012-01-02', periods=3))
        assert_series_equal(ts + s, expected)
        assert_series_equal(s + ts, expected)

        expected2 = Series(date_range('2011-12-31', periods=3, freq='-1D'))
        assert_series_equal(ts - s, expected2)
        assert_series_equal(ts + (-s), expected2)

    def test_timedelta64_operations_with_DateOffset(self):
        # GH 10699
        td = Series([timedelta(minutes=5, seconds=3)] * 3)
        result = td + pd.offsets.Minute(1)
        expected = Series([timedelta(minutes=6, seconds=3)] * 3)
        assert_series_equal(result, expected)

        result = td - pd.offsets.Minute(1)
        expected = Series([timedelta(minutes=4, seconds=3)] * 3)
        assert_series_equal(result, expected)

        result = td + Series([pd.offsets.Minute(1), pd.offsets.Second(3),
                              pd.offsets.Hour(2)])
        expected = Series([timedelta(minutes=6, seconds=3), timedelta(
            minutes=5, seconds=6), timedelta(hours=2, minutes=5, seconds=3)])
        assert_series_equal(result, expected)

        result = td + pd.offsets.Minute(1) + pd.offsets.Second(12)
        expected = Series([timedelta(minutes=6, seconds=15)] * 3)
        assert_series_equal(result, expected)

        # valid DateOffsets
        for do in ['Hour', 'Minute', 'Second', 'Day', 'Micro', 'Milli',
                   'Nano']:
            op = getattr(pd.offsets, do)
            td + op(5)
            op(5) + td
            td - op(5)
            op(5) - td

    def test_timedelta64_operations_with_timedeltas(self):

        # td operate with td
        td1 = Series([timedelta(minutes=5, seconds=3)] * 3)
        td2 = timedelta(minutes=5, seconds=4)
        result = td1 - td2
        expected = Series([timedelta(seconds=0)] * 3) - Series([timedelta(
            seconds=1)] * 3)
        self.assertEqual(result.dtype, 'm8[ns]')
        assert_series_equal(result, expected)

        result2 = td2 - td1
        expected = (Series([timedelta(seconds=1)] * 3) - Series([timedelta(
            seconds=0)] * 3))
        assert_series_equal(result2, expected)

        # roundtrip
        assert_series_equal(result + td2, td1)

        # Now again, using pd.to_timedelta, which should build
        # a Series or a scalar, depending on input.
        td1 = Series(pd.to_timedelta(['00:05:03'] * 3))
        td2 = pd.to_timedelta('00:05:04')
        result = td1 - td2
        expected = Series([timedelta(seconds=0)] * 3) - Series([timedelta(
            seconds=1)] * 3)
        self.assertEqual(result.dtype, 'm8[ns]')
        assert_series_equal(result, expected)

        result2 = td2 - td1
        expected = (Series([timedelta(seconds=1)] * 3) - Series([timedelta(
            seconds=0)] * 3))
        assert_series_equal(result2, expected)

        # roundtrip
        assert_series_equal(result + td2, td1)

    def test_timedelta64_operations_with_integers(self):

        # GH 4521
        # divide/multiply by integers
        startdate = Series(date_range('2013-01-01', '2013-01-03'))
        enddate = Series(date_range('2013-03-01', '2013-03-03'))

        s1 = enddate - startdate
        s1[2] = np.nan
        s2 = Series([2, 3, 4])
        expected = Series(s1.values.astype(np.int64) / s2, dtype='m8[ns]')
        expected[2] = np.nan
        result = s1 / s2
        assert_series_equal(result, expected)

        s2 = Series([20, 30, 40])
        expected = Series(s1.values.astype(np.int64) / s2, dtype='m8[ns]')
        expected[2] = np.nan
        result = s1 / s2
        assert_series_equal(result, expected)

        result = s1 / 2
        expected = Series(s1.values.astype(np.int64) / 2, dtype='m8[ns]')
        expected[2] = np.nan
        assert_series_equal(result, expected)

        s2 = Series([20, 30, 40])
        expected = Series(s1.values.astype(np.int64) * s2, dtype='m8[ns]')
        expected[2] = np.nan
        result = s1 * s2
        assert_series_equal(result, expected)

        for dtype in ['int32', 'int16', 'uint32', 'uint64', 'uint32', 'uint16',
                      'uint8']:
            s2 = Series([20, 30, 40], dtype=dtype)
            expected = Series(
                s1.values.astype(np.int64) * s2.astype(np.int64),
                dtype='m8[ns]')
            expected[2] = np.nan
            result = s1 * s2
            assert_series_equal(result, expected)

        result = s1 * 2
        expected = Series(s1.values.astype(np.int64) * 2, dtype='m8[ns]')
        expected[2] = np.nan
        assert_series_equal(result, expected)

        result = s1 * -1
        expected = Series(s1.values.astype(np.int64) * -1, dtype='m8[ns]')
        expected[2] = np.nan
        assert_series_equal(result, expected)

        # invalid ops
        assert_series_equal(s1 / s2.astype(float),
                            Series([Timedelta('2 days 22:48:00'), Timedelta(
                                '1 days 23:12:00'), Timedelta('NaT')]))
        assert_series_equal(s1 / 2.0,
                            Series([Timedelta('29 days 12:00:00'), Timedelta(
                                '29 days 12:00:00'), Timedelta('NaT')]))

        for op in ['__add__', '__sub__']:
            sop = getattr(s1, op, None)
            if sop is not None:
                self.assertRaises(TypeError, sop, 1)
                self.assertRaises(TypeError, sop, s2.values)

    def test_timedelta64_conversions(self):
        startdate = Series(date_range('2013-01-01', '2013-01-03'))
        enddate = Series(date_range('2013-03-01', '2013-03-03'))

        s1 = enddate - startdate
        s1[2] = np.nan

        for m in [1, 3, 10]:
            for unit in ['D', 'h', 'm', 's', 'ms', 'us', 'ns']:

                # op
                expected = s1.apply(lambda x: x / np.timedelta64(m, unit))
                result = s1 / np.timedelta64(m, unit)
                assert_series_equal(result, expected)

                if m == 1 and unit != 'ns':

                    # astype
                    result = s1.astype("timedelta64[{0}]".format(unit))
                    assert_series_equal(result, expected)

                # reverse op
                expected = s1.apply(
                    lambda x: Timedelta(np.timedelta64(m, unit)) / x)
                result = np.timedelta64(m, unit) / s1

        # astype
        s = Series(date_range('20130101', periods=3))
        result = s.astype(object)
        self.assertIsInstance(result.iloc[0], datetime)
        self.assertTrue(result.dtype == np.object_)

        result = s1.astype(object)
        self.assertIsInstance(result.iloc[0], timedelta)
        self.assertTrue(result.dtype == np.object_)

    def test_timedelta64_equal_timedelta_supported_ops(self):
        ser = Series([Timestamp('20130301'), Timestamp('20130228 23:00:00'),
                      Timestamp('20130228 22:00:00'), Timestamp(
                          '20130228 21:00:00')])

        intervals = 'D', 'h', 'm', 's', 'us'

        # TODO: unused
        # npy16_mappings = {'D': 24 * 60 * 60 * 1000000,
        #                   'h': 60 * 60 * 1000000,
        #                   'm': 60 * 1000000,
        #                   's': 1000000,
        #                   'us': 1}

        def timedelta64(*args):
            return sum(starmap(np.timedelta64, zip(args, intervals)))

        for op, d, h, m, s, us in product([operator.add, operator.sub],
                                          *([range(2)] * 5)):
            nptd = timedelta64(d, h, m, s, us)
            pytd = timedelta(days=d, hours=h, minutes=m, seconds=s,
                             microseconds=us)
            lhs = op(ser, nptd)
            rhs = op(ser, pytd)

            try:
                assert_series_equal(lhs, rhs)
            except:
                raise AssertionError(
                    "invalid comparsion [op->{0},d->{1},h->{2},m->{3},"
                    "s->{4},us->{5}]\n{6}\n{7}\n".format(op, d, h, m, s,
                                                         us, lhs, rhs))

    def test_operators_datetimelike(self):
        def run_ops(ops, get_ser, test_ser):

            # check that we are getting a TypeError
            # with 'operate' (from core/ops.py) for the ops that are not
            # defined
            for op_str in ops:
                op = getattr(get_ser, op_str, None)
                with tm.assertRaisesRegexp(TypeError, 'operate'):
                    op(test_ser)

        # ## timedelta64 ###
        td1 = Series([timedelta(minutes=5, seconds=3)] * 3)
        td1.iloc[2] = np.nan
        td2 = timedelta(minutes=5, seconds=4)
        ops = ['__mul__', '__floordiv__', '__pow__', '__rmul__',
               '__rfloordiv__', '__rpow__']
        run_ops(ops, td1, td2)
        td1 + td2
        td2 + td1
        td1 - td2
        td2 - td1
        td1 / td2
        td2 / td1

        # ## datetime64 ###
        dt1 = Series([Timestamp('20111230'), Timestamp('20120101'), Timestamp(
            '20120103')])
        dt1.iloc[2] = np.nan
        dt2 = Series([Timestamp('20111231'), Timestamp('20120102'), Timestamp(
            '20120104')])
        ops = ['__add__', '__mul__', '__floordiv__', '__truediv__', '__div__',
               '__pow__', '__radd__', '__rmul__', '__rfloordiv__',
               '__rtruediv__', '__rdiv__', '__rpow__']
        run_ops(ops, dt1, dt2)
        dt1 - dt2
        dt2 - dt1

        # ## datetime64 with timetimedelta ###
        ops = ['__mul__', '__floordiv__', '__truediv__', '__div__', '__pow__',
               '__rmul__', '__rfloordiv__', '__rtruediv__', '__rdiv__',
               '__rpow__']
        run_ops(ops, dt1, td1)
        dt1 + td1
        td1 + dt1
        dt1 - td1
        # TODO: Decide if this ought to work.
        # td1 - dt1

        # ## timetimedelta with datetime64 ###
        ops = ['__sub__', '__mul__', '__floordiv__', '__truediv__', '__div__',
               '__pow__', '__rmul__', '__rfloordiv__', '__rtruediv__',
               '__rdiv__', '__rpow__']
        run_ops(ops, td1, dt1)
        td1 + dt1
        dt1 + td1

        # 8260, 10763
        # datetime64 with tz
        ops = ['__mul__', '__floordiv__', '__truediv__', '__div__', '__pow__',
               '__rmul__', '__rfloordiv__', '__rtruediv__', '__rdiv__',
               '__rpow__']
        dt1 = Series(
            date_range('2000-01-01 09:00:00', periods=5,
                       tz='US/Eastern'), name='foo')
        dt2 = dt1.copy()
        dt2.iloc[2] = np.nan
        td1 = Series(timedelta_range('1 days 1 min', periods=5, freq='H'))
        td2 = td1.copy()
        td2.iloc[1] = np.nan
        run_ops(ops, dt1, td1)

        result = dt1 + td1[0]
        expected = (
            dt1.dt.tz_localize(None) + td1[0]).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        result = dt2 + td2[0]
        expected = (
            dt2.dt.tz_localize(None) + td2[0]).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        # odd numpy behavior with scalar timedeltas
        if not _np_version_under1p8:
            result = td1[0] + dt1
            expected = (
                dt1.dt.tz_localize(None) + td1[0]).dt.tz_localize('US/Eastern')
            assert_series_equal(result, expected)

            result = td2[0] + dt2
            expected = (
                dt2.dt.tz_localize(None) + td2[0]).dt.tz_localize('US/Eastern')
            assert_series_equal(result, expected)

        result = dt1 - td1[0]
        expected = (
            dt1.dt.tz_localize(None) - td1[0]).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)
        self.assertRaises(TypeError, lambda: td1[0] - dt1)

        result = dt2 - td2[0]
        expected = (
            dt2.dt.tz_localize(None) - td2[0]).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)
        self.assertRaises(TypeError, lambda: td2[0] - dt2)

        result = dt1 + td1
        expected = (
            dt1.dt.tz_localize(None) + td1).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        result = dt2 + td2
        expected = (
            dt2.dt.tz_localize(None) + td2).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        result = dt1 - td1
        expected = (
            dt1.dt.tz_localize(None) - td1).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        result = dt2 - td2
        expected = (
            dt2.dt.tz_localize(None) - td2).dt.tz_localize('US/Eastern')
        assert_series_equal(result, expected)

        self.assertRaises(TypeError, lambda: td1 - dt1)
        self.assertRaises(TypeError, lambda: td2 - dt2)

    def test_ops_nat(self):
        # GH 11349
        timedelta_series = Series([NaT, Timedelta('1s')])
        datetime_series = Series([NaT, Timestamp('19900315')])
        nat_series_dtype_timedelta = Series(
            [NaT, NaT], dtype='timedelta64[ns]')
        nat_series_dtype_timestamp = Series([NaT, NaT], dtype='datetime64[ns]')
        single_nat_dtype_datetime = Series([NaT], dtype='datetime64[ns]')
        single_nat_dtype_timedelta = Series([NaT], dtype='timedelta64[ns]')

        # subtraction
        assert_series_equal(timedelta_series - NaT, nat_series_dtype_timedelta)
        assert_series_equal(-NaT + timedelta_series,
                            nat_series_dtype_timedelta)

        assert_series_equal(timedelta_series - single_nat_dtype_timedelta,
                            nat_series_dtype_timedelta)
        assert_series_equal(-single_nat_dtype_timedelta + timedelta_series,
                            nat_series_dtype_timedelta)

        assert_series_equal(datetime_series - NaT, nat_series_dtype_timestamp)
        assert_series_equal(-NaT + datetime_series, nat_series_dtype_timestamp)

        assert_series_equal(datetime_series - single_nat_dtype_datetime,
                            nat_series_dtype_timedelta)
        with tm.assertRaises(TypeError):
            -single_nat_dtype_datetime + datetime_series

        assert_series_equal(datetime_series - single_nat_dtype_timedelta,
                            nat_series_dtype_timestamp)
        assert_series_equal(-single_nat_dtype_timedelta + datetime_series,
                            nat_series_dtype_timestamp)

        # without a Series wrapping the NaT, it is ambiguous
        # whether it is a datetime64 or timedelta64
        # defaults to interpreting it as timedelta64
        assert_series_equal(nat_series_dtype_timestamp - NaT,
                            nat_series_dtype_timestamp)
        assert_series_equal(-NaT + nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        assert_series_equal(nat_series_dtype_timestamp -
                            single_nat_dtype_datetime,
                            nat_series_dtype_timedelta)
        with tm.assertRaises(TypeError):
            -single_nat_dtype_datetime + nat_series_dtype_timestamp

        assert_series_equal(nat_series_dtype_timestamp -
                            single_nat_dtype_timedelta,
                            nat_series_dtype_timestamp)
        assert_series_equal(-single_nat_dtype_timedelta +
                            nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        with tm.assertRaises(TypeError):
            timedelta_series - single_nat_dtype_datetime

        # addition
        assert_series_equal(nat_series_dtype_timestamp + NaT,
                            nat_series_dtype_timestamp)
        assert_series_equal(NaT + nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        assert_series_equal(nat_series_dtype_timestamp +
                            single_nat_dtype_timedelta,
                            nat_series_dtype_timestamp)
        assert_series_equal(single_nat_dtype_timedelta +
                            nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        assert_series_equal(nat_series_dtype_timedelta + NaT,
                            nat_series_dtype_timedelta)
        assert_series_equal(NaT + nat_series_dtype_timedelta,
                            nat_series_dtype_timedelta)

        assert_series_equal(nat_series_dtype_timedelta +
                            single_nat_dtype_timedelta,
                            nat_series_dtype_timedelta)
        assert_series_equal(single_nat_dtype_timedelta +
                            nat_series_dtype_timedelta,
                            nat_series_dtype_timedelta)

        assert_series_equal(timedelta_series + NaT, nat_series_dtype_timedelta)
        assert_series_equal(NaT + timedelta_series, nat_series_dtype_timedelta)

        assert_series_equal(timedelta_series + single_nat_dtype_timedelta,
                            nat_series_dtype_timedelta)
        assert_series_equal(single_nat_dtype_timedelta + timedelta_series,
                            nat_series_dtype_timedelta)

        assert_series_equal(nat_series_dtype_timestamp + NaT,
                            nat_series_dtype_timestamp)
        assert_series_equal(NaT + nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        assert_series_equal(nat_series_dtype_timestamp +
                            single_nat_dtype_timedelta,
                            nat_series_dtype_timestamp)
        assert_series_equal(single_nat_dtype_timedelta +
                            nat_series_dtype_timestamp,
                            nat_series_dtype_timestamp)

        assert_series_equal(nat_series_dtype_timedelta + NaT,
                            nat_series_dtype_timedelta)
        assert_series_equal(NaT + nat_series_dtype_timedelta,
                            nat_series_dtype_timedelta)

        assert_series_equal(nat_series_dtype_timedelta +
                            single_nat_dtype_timedelta,
                            nat_series_dtype_timedelta)
        assert_series_equal(single_nat_dtype_timedelta +
                            nat_series_dtype_timedelta,
                            nat_series_dtype_timedelta)

        assert_series_equal(nat_series_dtype_timedelta +
                            single_nat_dtype_datetime,
                            nat_series_dtype_timestamp)
        assert_series_equal(single_nat_dtype_datetime +
                            nat_series_dtype_timedelta,
                            nat_series_dtype_timestamp)

        # multiplication
        assert_series_equal(nat_series_dtype_timedelta * 1.0,
                            nat_series_dtype_timedelta)
        assert_series_equal(1.0 * nat_series_dtype_timedelta,
                            nat_series_dtype_timedelta)

        assert_series_equal(timedelta_series * 1, timedelta_series)
        assert_series_equal(1 * timedelta_series, timedelta_series)

        assert_series_equal(timedelta_series * 1.5,
                            Series([NaT, Timedelta('1.5s')]))
        assert_series_equal(1.5 * timedelta_series,
                            Series([NaT, Timedelta('1.5s')]))

        assert_series_equal(timedelta_series * nan, nat_series_dtype_timedelta)
        assert_series_equal(nan * timedelta_series, nat_series_dtype_timedelta)

        with tm.assertRaises(TypeError):
            datetime_series * 1
        with tm.assertRaises(TypeError):
            nat_series_dtype_timestamp * 1
        with tm.assertRaises(TypeError):
            datetime_series * 1.0
        with tm.assertRaises(TypeError):
            nat_series_dtype_timestamp * 1.0

        # division
        assert_series_equal(timedelta_series / 2,
                            Series([NaT, Timedelta('0.5s')]))
        assert_series_equal(timedelta_series / 2.0,
                            Series([NaT, Timedelta('0.5s')]))
        assert_series_equal(timedelta_series / nan, nat_series_dtype_timedelta)
        with tm.assertRaises(TypeError):
            nat_series_dtype_timestamp / 1.0
        with tm.assertRaises(TypeError):
            nat_series_dtype_timestamp / 1

    def test_ops_datetimelike_align(self):
        # GH 7500
        # datetimelike ops need to align
        dt = Series(date_range('2012-1-1', periods=3, freq='D'))
        dt.iloc[2] = np.nan
        dt2 = dt[::-1]

        expected = Series([timedelta(0), timedelta(0), pd.NaT])
        # name is reset
        result = dt2 - dt
        assert_series_equal(result, expected)

        expected = Series(expected, name=0)
        result = (dt2.to_frame() - dt.to_frame())[0]
        assert_series_equal(result, expected)

    def test_object_comparisons(self):
        s = Series(['a', 'b', np.nan, 'c', 'a'])

        result = s == 'a'
        expected = Series([True, False, False, False, True])
        assert_series_equal(result, expected)

        result = s < 'a'
        expected = Series([False, False, False, False, False])
        assert_series_equal(result, expected)

        result = s != 'a'
        expected = -(s == 'a')
        assert_series_equal(result, expected)

    def test_comparison_tuples(self):
        # GH11339
        # comparisons vs tuple
        s = Series([(1, 1), (1, 2)])

        result = s == (1, 2)
        expected = Series([False, True])
        assert_series_equal(result, expected)

        result = s != (1, 2)
        expected = Series([True, False])
        assert_series_equal(result, expected)

        result = s == (0, 0)
        expected = Series([False, False])
        assert_series_equal(result, expected)

        result = s != (0, 0)
        expected = Series([True, True])
        assert_series_equal(result, expected)

        s = Series([(1, 1), (1, 1)])

        result = s == (1, 1)
        expected = Series([True, True])
        assert_series_equal(result, expected)

        result = s != (1, 1)
        expected = Series([False, False])
        assert_series_equal(result, expected)

        s = Series([frozenset([1]), frozenset([1, 2])])

        result = s == frozenset([1])
        expected = Series([True, False])
        assert_series_equal(result, expected)

    def test_comparison_operators_with_nas(self):
        s = Series(bdate_range('1/1/2000', periods=10), dtype=object)
        s[::2] = np.nan

        # test that comparisons work
        ops = ['lt', 'le', 'gt', 'ge', 'eq', 'ne']
        for op in ops:
            val = s[5]

            f = getattr(operator, op)
            result = f(s, val)

            expected = f(s.dropna(), val).reindex(s.index)

            if op == 'ne':
                expected = expected.fillna(True).astype(bool)
            else:
                expected = expected.fillna(False).astype(bool)

            assert_series_equal(result, expected)

            # fffffffuuuuuuuuuuuu
            # result = f(val, s)
            # expected = f(val, s.dropna()).reindex(s.index)
            # assert_series_equal(result, expected)

            # boolean &, |, ^ should work with object arrays and propagate NAs

        ops = ['and_', 'or_', 'xor']
        mask = s.isnull()
        for bool_op in ops:
            f = getattr(operator, bool_op)

            filled = s.fillna(s[0])

            result = f(s < s[9], s > s[3])

            expected = f(filled < filled[9], filled > filled[3])
            expected[mask] = False
            assert_series_equal(result, expected)

    def test_comparison_object_numeric_nas(self):
        s = Series(np.random.randn(10), dtype=object)
        shifted = s.shift(2)

        ops = ['lt', 'le', 'gt', 'ge', 'eq', 'ne']
        for op in ops:
            f = getattr(operator, op)

            result = f(s, shifted)
            expected = f(s.astype(float), shifted.astype(float))
            assert_series_equal(result, expected)

    def test_comparison_invalid(self):

        # GH4968
        # invalid date/int comparisons
        s = Series(range(5))
        s2 = Series(date_range('20010101', periods=5))

        for (x, y) in [(s, s2), (s2, s)]:
            self.assertRaises(TypeError, lambda: x == y)
            self.assertRaises(TypeError, lambda: x != y)
            self.assertRaises(TypeError, lambda: x >= y)
            self.assertRaises(TypeError, lambda: x > y)
            self.assertRaises(TypeError, lambda: x < y)
            self.assertRaises(TypeError, lambda: x <= y)

    def test_more_na_comparisons(self):
        left = Series(['a', np.nan, 'c'])
        right = Series(['a', np.nan, 'd'])

        result = left == right
        expected = Series([True, False, False])
        assert_series_equal(result, expected)

        result = left != right
        expected = Series([False, True, True])
        assert_series_equal(result, expected)

        result = left == np.nan
        expected = Series([False, False, False])
        assert_series_equal(result, expected)

        result = left != np.nan
        expected = Series([True, True, True])
        assert_series_equal(result, expected)

    def test_comparison_different_length(self):
        a = Series(['a', 'b', 'c'])
        b = Series(['b', 'a'])
        self.assertRaises(ValueError, a.__lt__, b)

        a = Series([1, 2])
        b = Series([2, 3, 4])
        self.assertRaises(ValueError, a.__eq__, b)

    def test_comparison_label_based(self):

        # GH 4947
        # comparisons should be label based

        a = Series([True, False, True], list('bca'))
        b = Series([False, True, False], list('abc'))

        expected = Series([True, False, False], list('bca'))
        result = a & b
        assert_series_equal(result, expected)

        expected = Series([True, False, True], list('bca'))
        result = a | b
        assert_series_equal(result, expected)

        expected = Series([False, False, True], list('bca'))
        result = a ^ b
        assert_series_equal(result, expected)

        # rhs is bigger
        a = Series([True, False, True], list('bca'))
        b = Series([False, True, False, True], list('abcd'))

        expected = Series([True, False, False], list('bca'))
        result = a & b
        assert_series_equal(result, expected)

        expected = Series([True, False, True], list('bca'))
        result = a | b
        assert_series_equal(result, expected)

        # filling

        # vs empty
        result = a & Series([])
        expected = Series([False, False, False], list('bca'))
        assert_series_equal(result, expected)

        result = a | Series([])
        expected = Series([True, False, True], list('bca'))
        assert_series_equal(result, expected)

        # vs non-matching
        result = a & Series([1], ['z'])
        expected = Series([False, False, False], list('bca'))
        assert_series_equal(result, expected)

        result = a | Series([1], ['z'])
        expected = Series([True, False, True], list('bca'))
        assert_series_equal(result, expected)

        # identity
        # we would like s[s|e] == s to hold for any e, whether empty or not
        for e in [Series([]), Series([1], ['z']), Series(['z']),
                  Series(np.nan, b.index), Series(np.nan, a.index)]:
            result = a[a | e]
            assert_series_equal(result, a[a])

        # vs scalars
        index = list('bca')
        t = Series([True, False, True])

        for v in [True, 1, 2]:
            result = Series([True, False, True], index=index) | v
            expected = Series([True, True, True], index=index)
            assert_series_equal(result, expected)

        for v in [np.nan, 'foo']:
            self.assertRaises(TypeError, lambda: t | v)

        for v in [False, 0]:
            result = Series([True, False, True], index=index) | v
            expected = Series([True, False, True], index=index)
            assert_series_equal(result, expected)

        for v in [True, 1]:
            result = Series([True, False, True], index=index) & v
            expected = Series([True, False, True], index=index)
            assert_series_equal(result, expected)

        for v in [False, 0]:
            result = Series([True, False, True], index=index) & v
            expected = Series([False, False, False], index=index)
            assert_series_equal(result, expected)
        for v in [np.nan]:
            self.assertRaises(TypeError, lambda: t & v)

    def test_operators_bitwise(self):
        # GH 9016: support bitwise op for integer types
        index = list('bca')

        s_tft = Series([True, False, True], index=index)
        s_fff = Series([False, False, False], index=index)
        s_tff = Series([True, False, False], index=index)
        s_empty = Series([])

        # TODO: unused
        # s_0101 = Series([0, 1, 0, 1])

        s_0123 = Series(range(4), dtype='int64')
        s_3333 = Series([3] * 4)
        s_4444 = Series([4] * 4)

        res = s_tft & s_empty
        expected = s_fff
        assert_series_equal(res, expected)

        res = s_tft | s_empty
        expected = s_tft
        assert_series_equal(res, expected)

        res = s_0123 & s_3333
        expected = Series(range(4), dtype='int64')
        assert_series_equal(res, expected)

        res = s_0123 | s_4444
        expected = Series(range(4, 8), dtype='int64')
        assert_series_equal(res, expected)

        s_a0b1c0 = Series([1], list('b'))

        res = s_tft & s_a0b1c0
        expected = s_tff
        assert_series_equal(res, expected)

        res = s_tft | s_a0b1c0
        expected = s_tft
        assert_series_equal(res, expected)

        n0 = 0
        res = s_tft & n0
        expected = s_fff
        assert_series_equal(res, expected)

        res = s_0123 & n0
        expected = Series([0] * 4)
        assert_series_equal(res, expected)

        n1 = 1
        res = s_tft & n1
        expected = s_tft
        assert_series_equal(res, expected)

        res = s_0123 & n1
        expected = Series([0, 1, 0, 1])
        assert_series_equal(res, expected)

        s_1111 = Series([1] * 4, dtype='int8')
        res = s_0123 & s_1111
        expected = Series([0, 1, 0, 1], dtype='int64')
        assert_series_equal(res, expected)

        res = s_0123.astype(np.int16) | s_1111.astype(np.int32)
        expected = Series([1, 1, 3, 3], dtype='int32')
        assert_series_equal(res, expected)

        self.assertRaises(TypeError, lambda: s_1111 & 'a')
        self.assertRaises(TypeError, lambda: s_1111 & ['a', 'b', 'c', 'd'])
        self.assertRaises(TypeError, lambda: s_0123 & np.NaN)
        self.assertRaises(TypeError, lambda: s_0123 & 3.14)
        self.assertRaises(TypeError, lambda: s_0123 & [0.1, 4, 3.14, 2])

        # s_0123 will be all false now because of reindexing like s_tft
        assert_series_equal(s_tft & s_0123, Series([False] * 3, list('bca')))
        # s_tft will be all false now because of reindexing like s_0123
        assert_series_equal(s_0123 & s_tft, Series([False] * 4))
        assert_series_equal(s_0123 & False, Series([False] * 4))
        assert_series_equal(s_0123 ^ False, Series([False, True, True, True]))
        assert_series_equal(s_0123 & [False], Series([False] * 4))
        assert_series_equal(s_0123 & (False), Series([False] * 4))
        assert_series_equal(s_0123 & Series([False, np.NaN, False, False]),
                            Series([False] * 4))

        s_ftft = Series([False, True, False, True])
        assert_series_equal(s_0123 & Series([0.1, 4, -3.14, 2]), s_ftft)

        s_abNd = Series(['a', 'b', np.NaN, 'd'])
        res = s_0123 & s_abNd
        expected = s_ftft
        assert_series_equal(res, expected)

    def test_scalar_na_cmp_corners(self):
        s = Series([2, 3, 4, 5, 6, 7, 8, 9, 10])

        def tester(a, b):
            return a & b

        self.assertRaises(TypeError, tester, s, datetime(2005, 1, 1))

        s = Series([2, 3, 4, 5, 6, 7, 8, 9, datetime(2005, 1, 1)])
        s[::2] = np.nan

        expected = Series(True, index=s.index)
        expected[::2] = False
        assert_series_equal(tester(s, list(s)), expected)

        d = DataFrame({'A': s})
        # TODO: Fix this exception - needs to be fixed! (see GH5035)
        # (previously this was a TypeError because series returned
        # NotImplemented
        self.assertRaises(ValueError, tester, s, d)

    def test_operators_corner(self):
        series = self.ts

        empty = Series([], index=Index([]))

        result = series + empty
        self.assertTrue(np.isnan(result).all())

        result = empty + Series([], index=Index([]))
        self.assertEqual(len(result), 0)

        # TODO: this returned NotImplemented earlier, what to do?
        # deltas = Series([timedelta(1)] * 5, index=np.arange(5))
        # sub_deltas = deltas[::2]
        # deltas5 = deltas * 5
        # deltas = deltas + sub_deltas

        # float + int
        int_ts = self.ts.astype(int)[:-5]
        added = self.ts + int_ts
        expected = self.ts.values[:-5] + int_ts.values
        self.assert_numpy_array_equal(added[:-5], expected)

    def test_operators_reverse_object(self):
        # GH 56
        arr = Series(np.random.randn(10), index=np.arange(10), dtype=object)

        def _check_op(arr, op):
            result = op(1., arr)
            expected = op(1., arr.astype(float))
            assert_series_equal(result.astype(float), expected)

        _check_op(arr, operator.add)
        _check_op(arr, operator.sub)
        _check_op(arr, operator.mul)
        _check_op(arr, operator.truediv)
        _check_op(arr, operator.floordiv)

    def test_series_frame_radd_bug(self):
        import operator

        # GH 353
        vals = Series(tm.rands_array(5, 10))
        result = 'foo_' + vals
        expected = vals.map(lambda x: 'foo_' + x)
        assert_series_equal(result, expected)

        frame = DataFrame({'vals': vals})
        result = 'foo_' + frame
        expected = DataFrame({'vals': vals.map(lambda x: 'foo_' + x)})
        tm.assert_frame_equal(result, expected)

        # really raise this time
        self.assertRaises(TypeError, operator.add, datetime.now(), self.ts)

    def test_operators_frame(self):
        # rpow does not work with DataFrame
        df = DataFrame({'A': self.ts})

        tm.assert_almost_equal(self.ts + self.ts, self.ts + df['A'])
        tm.assert_almost_equal(self.ts ** self.ts, self.ts ** df['A'])
        tm.assert_almost_equal(self.ts < self.ts, self.ts < df['A'])
        tm.assert_almost_equal(self.ts / self.ts, self.ts / df['A'])

    def test_operators_combine(self):
        def _check_fill(meth, op, a, b, fill_value=0):
            exp_index = a.index.union(b.index)
            a = a.reindex(exp_index)
            b = b.reindex(exp_index)

            amask = isnull(a)
            bmask = isnull(b)

            exp_values = []
            for i in range(len(exp_index)):
                if amask[i]:
                    if bmask[i]:
                        exp_values.append(nan)
                        continue
                    exp_values.append(op(fill_value, b[i]))
                elif bmask[i]:
                    if amask[i]:
                        exp_values.append(nan)
                        continue
                    exp_values.append(op(a[i], fill_value))
                else:
                    exp_values.append(op(a[i], b[i]))

            result = meth(a, b, fill_value=fill_value)
            expected = Series(exp_values, exp_index)
            assert_series_equal(result, expected)

        a = Series([nan, 1., 2., 3., nan], index=np.arange(5))
        b = Series([nan, 1, nan, 3, nan, 4.], index=np.arange(6))

        pairings = []
        for op in ['add', 'sub', 'mul', 'pow', 'truediv', 'floordiv']:
            fv = 0
            lop = getattr(Series, op)
            lequiv = getattr(operator, op)
            rop = getattr(Series, 'r' + op)
            # bind op at definition time...
            requiv = lambda x, y, op=op: getattr(operator, op)(y, x)
            pairings.append((lop, lequiv, fv))
            pairings.append((rop, requiv, fv))

        if compat.PY3:
            pairings.append((Series.div, operator.truediv, 1))
            pairings.append((Series.rdiv, lambda x, y: operator.truediv(y, x),
                             1))
        else:
            pairings.append((Series.div, operator.div, 1))
            pairings.append((Series.rdiv, lambda x, y: operator.div(y, x), 1))

        for op, equiv_op, fv in pairings:
            result = op(a, b)
            exp = equiv_op(a, b)
            assert_series_equal(result, exp)
            _check_fill(op, equiv_op, a, b, fill_value=fv)
            # should accept axis=0 or axis='rows'
            op(a, b, axis=0)

    def test_ne(self):
        ts = Series([3, 4, 5, 6, 7], [3, 4, 5, 6, 7], dtype=float)
        expected = [True, True, False, True, True]
        self.assertTrue(tm.equalContents(ts.index != 5, expected))
        self.assertTrue(tm.equalContents(~(ts.index == 5), expected))

    def test_operators_na_handling(self):
        from decimal import Decimal
        from datetime import date
        s = Series([Decimal('1.3'), Decimal('2.3')],
                   index=[date(2012, 1, 1), date(2012, 1, 2)])

        result = s + s.shift(1)
        result2 = s.shift(1) + s
        self.assertTrue(isnull(result[0]))
        self.assertTrue(isnull(result2[0]))

        s = Series(['foo', 'bar', 'baz', np.nan])
        result = 'prefix_' + s
        expected = Series(['prefix_foo', 'prefix_bar', 'prefix_baz', np.nan])
        assert_series_equal(result, expected)

        result = s + '_suffix'
        expected = Series(['foo_suffix', 'bar_suffix', 'baz_suffix', np.nan])
        assert_series_equal(result, expected)

    def test_divide_decimal(self):
        ''' resolves issue #9787 '''
        from decimal import Decimal

        expected = Series([Decimal(5)])

        s = Series([Decimal(10)])
        s = s / Decimal(2)

        tm.assert_series_equal(expected, s)

        s = Series([Decimal(10)])
        s = s // Decimal(2)

        tm.assert_series_equal(expected, s)

    def test_datetime64_with_index(self):

        # arithmetic integer ops with an index
        s = Series(np.random.randn(5))
        expected = s - s.index.to_series()
        result = s - s.index
        assert_series_equal(result, expected)

        # GH 4629
        # arithmetic datetime64 ops with an index
        s = Series(date_range('20130101', periods=5),
                   index=date_range('20130101', periods=5))
        expected = s - s.index.to_series()
        result = s - s.index
        assert_series_equal(result, expected)

        result = s - s.index.to_period()
        assert_series_equal(result, expected)

        df = DataFrame(np.random.randn(5, 2),
                       index=date_range('20130101', periods=5))
        df['date'] = Timestamp('20130102')
        df['expected'] = df['date'] - df.index.to_series()
        df['result'] = df['date'] - df.index
        assert_series_equal(df['result'], df['expected'], check_names=False)