test_range.py

# -*- coding: utf-8 -*-

import pytest

from datetime import datetime
from itertools import combinations
import operator

from pandas.compat import range, u, PY3

import numpy as np

from pandas import (isna, Series, Index, Float64Index,
                    Int64Index, RangeIndex)

import pandas.util.testing as tm

import pandas as pd

from .test_numeric import Numeric


class TestRangeIndex(Numeric):
    _holder = RangeIndex
    _compat_props = ['shape', 'ndim', 'size']

    def setup_method(self, method):
        self.indices = dict(index=RangeIndex(0, 20, 2, name='foo'),
                            index_dec=RangeIndex(18, -1, -2, name='bar'))
        self.setup_indices()

    def create_index(self):
        return RangeIndex(5)

    def check_binop(self, ops, scalars, idxs):
        for op in ops:
            for a, b in combinations(idxs, 2):
                result = op(a, b)
                expected = op(Int64Index(a), Int64Index(b))
                tm.assert_index_equal(result, expected)
            for idx in idxs:
                for scalar in scalars:
                    result = op(idx, scalar)
                    expected = op(Int64Index(idx), scalar)
                    tm.assert_index_equal(result, expected)

    def test_can_hold_identifiers(self):
        idx = self.create_index()
        key = idx[0]
        assert idx._can_hold_identifiers_and_holds_name(key) is False

    def test_binops(self):
        ops = [operator.add, operator.sub, operator.mul, operator.floordiv,
               operator.truediv]
        scalars = [-1, 1, 2]
        idxs = [RangeIndex(0, 10, 1), RangeIndex(0, 20, 2),
                RangeIndex(-10, 10, 2), RangeIndex(5, -5, -1)]
        self.check_binop(ops, scalars, idxs)

    def test_binops_pow(self):
        # later versions of numpy don't allow powers of negative integers
        # so test separately
        # https://github.com/numpy/numpy/pull/8127
        ops = [pow]
        scalars = [1, 2]
        idxs = [RangeIndex(0, 10, 1), RangeIndex(0, 20, 2)]
        self.check_binop(ops, scalars, idxs)

    def test_too_many_names(self):
        def testit():
            self.index.names = ["roger", "harold"]

        tm.assert_raises_regex(ValueError, "^Length", testit)

    def test_constructor(self):
        index = RangeIndex(5)
        expected = np.arange(5, dtype=np.int64)
        assert isinstance(index, RangeIndex)
        assert index._start == 0
        assert index._stop == 5
        assert index._step == 1
        assert index.name is None
        tm.assert_index_equal(Index(expected), index)

        index = RangeIndex(1, 5)
        expected = np.arange(1, 5, dtype=np.int64)
        assert isinstance(index, RangeIndex)
        assert index._start == 1
        tm.assert_index_equal(Index(expected), index)

        index = RangeIndex(1, 5, 2)
        expected = np.arange(1, 5, 2, dtype=np.int64)
        assert isinstance(index, RangeIndex)
        assert index._step == 2
        tm.assert_index_equal(Index(expected), index)

        msg = "RangeIndex\\(\\.\\.\\.\\) must be called with integers"
        with tm.assert_raises_regex(TypeError, msg):
            RangeIndex()

        for index in [RangeIndex(0), RangeIndex(start=0), RangeIndex(stop=0),
                      RangeIndex(0, 0)]:
            expected = np.empty(0, dtype=np.int64)
            assert isinstance(index, RangeIndex)
            assert index._start == 0
            assert index._stop == 0
            assert index._step == 1
            tm.assert_index_equal(Index(expected), index)

        with tm.assert_raises_regex(TypeError, msg):
            RangeIndex(name='Foo')

        for index in [RangeIndex(0, name='Foo'),
                      RangeIndex(start=0, name='Foo'),
                      RangeIndex(stop=0, name='Foo'),
                      RangeIndex(0, 0, name='Foo')]:
            assert isinstance(index, RangeIndex)
            assert index.name == 'Foo'

        # we don't allow on a bare Index
        pytest.raises(TypeError, lambda: Index(0, 1000))

        # invalid args
        for i in [Index(['a', 'b']), Series(['a', 'b']), np.array(['a', 'b']),
                  [], 'foo', datetime(2000, 1, 1, 0, 0), np.arange(0, 10),
                  np.array([1]), [1]]:
            pytest.raises(TypeError, lambda: RangeIndex(i))

    def test_constructor_same(self):

        # pass thru w and w/o copy
        index = RangeIndex(1, 5, 2)
        result = RangeIndex(index, copy=False)
        assert result.identical(index)

        result = RangeIndex(index, copy=True)
        tm.assert_index_equal(result, index, exact=True)

        result = RangeIndex(index)
        tm.assert_index_equal(result, index, exact=True)

        pytest.raises(TypeError,
                      lambda: RangeIndex(index, dtype='float64'))

    def test_constructor_range(self):

        pytest.raises(TypeError, lambda: RangeIndex(range(1, 5, 2)))

        result = RangeIndex.from_range(range(1, 5, 2))
        expected = RangeIndex(1, 5, 2)
        tm.assert_index_equal(result, expected, exact=True)

        result = RangeIndex.from_range(range(5, 6))
        expected = RangeIndex(5, 6, 1)
        tm.assert_index_equal(result, expected, exact=True)

        # an invalid range
        result = RangeIndex.from_range(range(5, 1))
        expected = RangeIndex(0, 0, 1)
        tm.assert_index_equal(result, expected, exact=True)

        result = RangeIndex.from_range(range(5))
        expected = RangeIndex(0, 5, 1)
        tm.assert_index_equal(result, expected, exact=True)

        result = Index(range(1, 5, 2))
        expected = RangeIndex(1, 5, 2)
        tm.assert_index_equal(result, expected, exact=True)

        pytest.raises(TypeError,
                      lambda: Index(range(1, 5, 2), dtype='float64'))

    def test_constructor_name(self):
        # GH12288
        orig = RangeIndex(10)
        orig.name = 'original'

        copy = RangeIndex(orig)
        copy.name = 'copy'

        assert orig.name == 'original'
        assert copy.name == 'copy'

        new = Index(copy)
        assert new.name == 'copy'

        new.name = 'new'
        assert orig.name == 'original'
        assert copy.name == 'copy'
        assert new.name == 'new'

    # TODO: mod, divmod?
    @pytest.mark.parametrize('op', [operator.add, operator.sub,
                                    operator.mul, operator.floordiv,
                                    operator.truediv, operator.pow])
    def test_arithmetic_with_frame_or_series(self, op):
        # check that we return NotImplemented when operating with Series
        # or DataFrame
        index = pd.RangeIndex(5)
        other = pd.Series(np.random.randn(5))

        expected = op(pd.Series(index), other)
        result = op(index, other)
        tm.assert_series_equal(result, expected)

        other = pd.DataFrame(np.random.randn(2, 5))
        expected = op(pd.DataFrame([index, index]), other)
        result = op(index, other)
        tm.assert_frame_equal(result, expected)

    def test_numeric_compat2(self):
        # validate that we are handling the RangeIndex overrides to numeric ops
        # and returning RangeIndex where possible

        idx = RangeIndex(0, 10, 2)

        result = idx * 2
        expected = RangeIndex(0, 20, 4)
        tm.assert_index_equal(result, expected, exact=True)

        result = idx + 2
        expected = RangeIndex(2, 12, 2)
        tm.assert_index_equal(result, expected, exact=True)

        result = idx - 2
        expected = RangeIndex(-2, 8, 2)
        tm.assert_index_equal(result, expected, exact=True)

        # truediv under PY3
        result = idx / 2

        if PY3:
            expected = RangeIndex(0, 5, 1).astype('float64')
        else:
            expected = RangeIndex(0, 5, 1)
        tm.assert_index_equal(result, expected, exact=True)

        result = idx / 4
        expected = RangeIndex(0, 10, 2) / 4
        tm.assert_index_equal(result, expected, exact=True)

        result = idx // 1
        expected = idx
        tm.assert_index_equal(result, expected, exact=True)

        # __mul__
        result = idx * idx
        expected = Index(idx.values * idx.values)
        tm.assert_index_equal(result, expected, exact=True)

        # __pow__
        idx = RangeIndex(0, 1000, 2)
        result = idx ** 2
        expected = idx._int64index ** 2
        tm.assert_index_equal(Index(result.values), expected, exact=True)

        # __floordiv__
        cases_exact = [(RangeIndex(0, 1000, 2), 2, RangeIndex(0, 500, 1)),
                       (RangeIndex(-99, -201, -3), -3, RangeIndex(33, 67, 1)),
                       (RangeIndex(0, 1000, 1), 2,
                        RangeIndex(0, 1000, 1)._int64index // 2),
                       (RangeIndex(0, 100, 1), 2.0,
                        RangeIndex(0, 100, 1)._int64index // 2.0),
                       (RangeIndex(0), 50, RangeIndex(0)),
                       (RangeIndex(2, 4, 2), 3, RangeIndex(0, 1, 1)),
                       (RangeIndex(-5, -10, -6), 4, RangeIndex(-2, -1, 1)),
                       (RangeIndex(-100, -200, 3), 2, RangeIndex(0))]
        for idx, div, expected in cases_exact:
            tm.assert_index_equal(idx // div, expected, exact=True)

    def test_constructor_corner(self):
        arr = np.array([1, 2, 3, 4], dtype=object)
        index = RangeIndex(1, 5)
        assert index.values.dtype == np.int64
        tm.assert_index_equal(index, Index(arr))

        # non-int raise Exception
        pytest.raises(TypeError, RangeIndex, '1', '10', '1')
        pytest.raises(TypeError, RangeIndex, 1.1, 10.2, 1.3)

        # invalid passed type
        pytest.raises(TypeError, lambda: RangeIndex(1, 5, dtype='float64'))

    def test_copy(self):
        i = RangeIndex(5, name='Foo')
        i_copy = i.copy()
        assert i_copy is not i
        assert i_copy.identical(i)
        assert i_copy._start == 0
        assert i_copy._stop == 5
        assert i_copy._step == 1
        assert i_copy.name == 'Foo'

    def test_repr(self):
        i = RangeIndex(5, name='Foo')
        result = repr(i)
        if PY3:
            expected = "RangeIndex(start=0, stop=5, step=1, name='Foo')"
        else:
            expected = "RangeIndex(start=0, stop=5, step=1, name=u'Foo')"
        assert result == expected

        result = eval(result)
        tm.assert_index_equal(result, i, exact=True)

        i = RangeIndex(5, 0, -1)
        result = repr(i)
        expected = "RangeIndex(start=5, stop=0, step=-1)"
        assert result == expected

        result = eval(result)
        tm.assert_index_equal(result, i, exact=True)

    def test_insert(self):

        idx = RangeIndex(5, name='Foo')
        result = idx[1:4]

        # test 0th element
        tm.assert_index_equal(idx[0:4], result.insert(0, idx[0]))

        # GH 18295 (test missing)
        expected = Float64Index([0, np.nan, 1, 2, 3, 4])
        for na in (np.nan, pd.NaT, None):
            result = RangeIndex(5).insert(1, na)
            tm.assert_index_equal(result, expected)

    def test_delete(self):

        idx = RangeIndex(5, name='Foo')
        expected = idx[1:].astype(int)
        result = idx.delete(0)
        tm.assert_index_equal(result, expected)
        assert result.name == expected.name

        expected = idx[:-1].astype(int)
        result = idx.delete(-1)
        tm.assert_index_equal(result, expected)
        assert result.name == expected.name

        with pytest.raises((IndexError, ValueError)):
            # either depending on numpy version
            result = idx.delete(len(idx))

    def test_view(self, indices):
        super(TestRangeIndex, self).test_view(indices)

        i = RangeIndex(0, name='Foo')
        i_view = i.view()
        assert i_view.name == 'Foo'

        i_view = i.view('i8')
        tm.assert_numpy_array_equal(i.values, i_view)

        i_view = i.view(RangeIndex)
        tm.assert_index_equal(i, i_view)

    def test_dtype(self):
        assert self.index.dtype == np.int64

    def test_is_monotonic(self):
        assert self.index.is_monotonic is True
        assert self.index.is_monotonic_increasing is True
        assert self.index.is_monotonic_decreasing is False
        assert self.index._is_strictly_monotonic_increasing is True
        assert self.index._is_strictly_monotonic_decreasing is False

        index = RangeIndex(4, 0, -1)
        assert index.is_monotonic is False
        assert index._is_strictly_monotonic_increasing is False
        assert index.is_monotonic_decreasing is True
        assert index._is_strictly_monotonic_decreasing is True

        index = RangeIndex(1, 2)
        assert index.is_monotonic is True
        assert index.is_monotonic_increasing is True
        assert index.is_monotonic_decreasing is True
        assert index._is_strictly_monotonic_increasing is True
        assert index._is_strictly_monotonic_decreasing is True

        index = RangeIndex(2, 1)
        assert index.is_monotonic is True
        assert index.is_monotonic_increasing is True
        assert index.is_monotonic_decreasing is True
        assert index._is_strictly_monotonic_increasing is True
        assert index._is_strictly_monotonic_decreasing is True

        index = RangeIndex(1, 1)
        assert index.is_monotonic is True
        assert index.is_monotonic_increasing is True
        assert index.is_monotonic_decreasing is True
        assert index._is_strictly_monotonic_increasing is True
        assert index._is_strictly_monotonic_decreasing is True

    def test_equals_range(self):
        equiv_pairs = [(RangeIndex(0, 9, 2), RangeIndex(0, 10, 2)),
                       (RangeIndex(0), RangeIndex(1, -1, 3)),
                       (RangeIndex(1, 2, 3), RangeIndex(1, 3, 4)),
                       (RangeIndex(0, -9, -2), RangeIndex(0, -10, -2))]
        for left, right in equiv_pairs:
            assert left.equals(right)
            assert right.equals(left)

    def test_logical_compat(self):
        idx = self.create_index()
        assert idx.all() == idx.values.all()
        assert idx.any() == idx.values.any()

    def test_identical(self):
        i = Index(self.index.copy())
        assert i.identical(self.index)

        # we don't allow object dtype for RangeIndex
        if isinstance(self.index, RangeIndex):
            return

        same_values_different_type = Index(i, dtype=object)
        assert not i.identical(same_values_different_type)

        i = self.index.copy(dtype=object)
        i = i.rename('foo')
        same_values = Index(i, dtype=object)
        assert same_values.identical(self.index.copy(dtype=object))

        assert not i.identical(self.index)
        assert Index(same_values, name='foo', dtype=object).identical(i)

        assert not self.index.copy(dtype=object).identical(
            self.index.copy(dtype='int64'))

    def test_get_indexer(self):
        target = RangeIndex(10)
        indexer = self.index.get_indexer(target)
        expected = np.array([0, -1, 1, -1, 2, -1, 3, -1, 4, -1], dtype=np.intp)
        tm.assert_numpy_array_equal(indexer, expected)

    def test_get_indexer_pad(self):
        target = RangeIndex(10)
        indexer = self.index.get_indexer(target, method='pad')
        expected = np.array([0, 0, 1, 1, 2, 2, 3, 3, 4, 4], dtype=np.intp)
        tm.assert_numpy_array_equal(indexer, expected)

    def test_get_indexer_backfill(self):
        target = RangeIndex(10)
        indexer = self.index.get_indexer(target, method='backfill')
        expected = np.array([0, 1, 1, 2, 2, 3, 3, 4, 4, 5], dtype=np.intp)
        tm.assert_numpy_array_equal(indexer, expected)

    def test_join_outer(self):
        # join with Int64Index
        other = Int64Index(np.arange(25, 14, -1))

        res, lidx, ridx = self.index.join(other, how='outer',
                                          return_indexers=True)
        noidx_res = self.index.join(other, how='outer')
        tm.assert_index_equal(res, noidx_res)

        eres = Int64Index([0, 2, 4, 6, 8, 10, 12, 14, 15, 16, 17, 18, 19, 20,
                           21, 22, 23, 24, 25])
        elidx = np.array([0, 1, 2, 3, 4, 5, 6, 7, -1, 8, -1, 9,
                          -1, -1, -1, -1, -1, -1, -1], dtype=np.intp)
        eridx = np.array([-1, -1, -1, -1, -1, -1, -1, -1, 10, 9, 8, 7, 6,
                          5, 4, 3, 2, 1, 0], dtype=np.intp)

        assert isinstance(res, Int64Index)
        assert not isinstance(res, RangeIndex)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        tm.assert_numpy_array_equal(ridx, eridx)

        # join with RangeIndex
        other = RangeIndex(25, 14, -1)

        res, lidx, ridx = self.index.join(other, how='outer',
                                          return_indexers=True)
        noidx_res = self.index.join(other, how='outer')
        tm.assert_index_equal(res, noidx_res)

        assert isinstance(res, Int64Index)
        assert not isinstance(res, RangeIndex)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        tm.assert_numpy_array_equal(ridx, eridx)

    def test_join_inner(self):
        # Join with non-RangeIndex
        other = Int64Index(np.arange(25, 14, -1))

        res, lidx, ridx = self.index.join(other, how='inner',
                                          return_indexers=True)

        # no guarantee of sortedness, so sort for comparison purposes
        ind = res.argsort()
        res = res.take(ind)
        lidx = lidx.take(ind)
        ridx = ridx.take(ind)

        eres = Int64Index([16, 18])
        elidx = np.array([8, 9], dtype=np.intp)
        eridx = np.array([9, 7], dtype=np.intp)

        assert isinstance(res, Int64Index)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        tm.assert_numpy_array_equal(ridx, eridx)

        # Join two RangeIndex
        other = RangeIndex(25, 14, -1)

        res, lidx, ridx = self.index.join(other, how='inner',
                                          return_indexers=True)

        assert isinstance(res, RangeIndex)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        tm.assert_numpy_array_equal(ridx, eridx)

    def test_join_left(self):
        # Join with Int64Index
        other = Int64Index(np.arange(25, 14, -1))

        res, lidx, ridx = self.index.join(other, how='left',
                                          return_indexers=True)
        eres = self.index
        eridx = np.array([-1, -1, -1, -1, -1, -1, -1, -1, 9, 7], dtype=np.intp)

        assert isinstance(res, RangeIndex)
        tm.assert_index_equal(res, eres)
        assert lidx is None
        tm.assert_numpy_array_equal(ridx, eridx)

        # Join withRangeIndex
        other = Int64Index(np.arange(25, 14, -1))

        res, lidx, ridx = self.index.join(other, how='left',
                                          return_indexers=True)

        assert isinstance(res, RangeIndex)
        tm.assert_index_equal(res, eres)
        assert lidx is None
        tm.assert_numpy_array_equal(ridx, eridx)

    def test_join_right(self):
        # Join with Int64Index
        other = Int64Index(np.arange(25, 14, -1))

        res, lidx, ridx = self.index.join(other, how='right',
                                          return_indexers=True)
        eres = other
        elidx = np.array([-1, -1, -1, -1, -1, -1, -1, 9, -1, 8, -1],
                         dtype=np.intp)

        assert isinstance(other, Int64Index)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        assert ridx is None

        # Join withRangeIndex
        other = RangeIndex(25, 14, -1)

        res, lidx, ridx = self.index.join(other, how='right',
                                          return_indexers=True)
        eres = other

        assert isinstance(other, RangeIndex)
        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        assert ridx is None

    def test_join_non_int_index(self):
        other = Index([3, 6, 7, 8, 10], dtype=object)

        outer = self.index.join(other, how='outer')
        outer2 = other.join(self.index, how='outer')
        expected = Index([0, 2, 3, 4, 6, 7, 8, 10, 12, 14, 16, 18])
        tm.assert_index_equal(outer, outer2)
        tm.assert_index_equal(outer, expected)

        inner = self.index.join(other, how='inner')
        inner2 = other.join(self.index, how='inner')
        expected = Index([6, 8, 10])
        tm.assert_index_equal(inner, inner2)
        tm.assert_index_equal(inner, expected)

        left = self.index.join(other, how='left')
        tm.assert_index_equal(left, self.index.astype(object))

        left2 = other.join(self.index, how='left')
        tm.assert_index_equal(left2, other)

        right = self.index.join(other, how='right')
        tm.assert_index_equal(right, other)

        right2 = other.join(self.index, how='right')
        tm.assert_index_equal(right2, self.index.astype(object))

    def test_join_non_unique(self):
        other = Index([4, 4, 3, 3])

        res, lidx, ridx = self.index.join(other, return_indexers=True)

        eres = Int64Index([0, 2, 4, 4, 6, 8, 10, 12, 14, 16, 18])
        elidx = np.array([0, 1, 2, 2, 3, 4, 5, 6, 7, 8, 9], dtype=np.intp)
        eridx = np.array([-1, -1, 0, 1, -1, -1, -1, -1, -1, -1, -1],
                         dtype=np.intp)

        tm.assert_index_equal(res, eres)
        tm.assert_numpy_array_equal(lidx, elidx)
        tm.assert_numpy_array_equal(ridx, eridx)

    def test_join_self(self):
        kinds = 'outer', 'inner', 'left', 'right'
        for kind in kinds:
            joined = self.index.join(self.index, how=kind)
            assert self.index is joined

    def test_intersection(self):
        # intersect with Int64Index
        other = Index(np.arange(1, 6))
        result = self.index.intersection(other)
        expected = Index(np.sort(np.intersect1d(self.index.values,
                                                other.values)))
        tm.assert_index_equal(result, expected)

        result = other.intersection(self.index)
        expected = Index(np.sort(np.asarray(np.intersect1d(self.index.values,
                                                           other.values))))
        tm.assert_index_equal(result, expected)

        # intersect with increasing RangeIndex
        other = RangeIndex(1, 6)
        result = self.index.intersection(other)
        expected = Index(np.sort(np.intersect1d(self.index.values,
                                                other.values)))
        tm.assert_index_equal(result, expected)

        # intersect with decreasing RangeIndex
        other = RangeIndex(5, 0, -1)
        result = self.index.intersection(other)
        expected = Index(np.sort(np.intersect1d(self.index.values,
                                                other.values)))
        tm.assert_index_equal(result, expected)

        # reversed (GH 17296)
        result = other.intersection(self.index)
        tm.assert_index_equal(result, expected)

        # GH 17296: intersect two decreasing RangeIndexes
        first = RangeIndex(10, -2, -2)
        other = RangeIndex(5, -4, -1)
        expected = first.astype(int).intersection(other.astype(int))
        result = first.intersection(other).astype(int)
        tm.assert_index_equal(result, expected)

        # reversed
        result = other.intersection(first).astype(int)
        tm.assert_index_equal(result, expected)

        index = RangeIndex(5)

        # intersect of non-overlapping indices
        other = RangeIndex(5, 10, 1)
        result = index.intersection(other)
        expected = RangeIndex(0, 0, 1)
        tm.assert_index_equal(result, expected)

        other = RangeIndex(-1, -5, -1)
        result = index.intersection(other)
        expected = RangeIndex(0, 0, 1)
        tm.assert_index_equal(result, expected)

        # intersection of empty indices
        other = RangeIndex(0, 0, 1)
        result = index.intersection(other)
        expected = RangeIndex(0, 0, 1)
        tm.assert_index_equal(result, expected)

        result = other.intersection(index)
        tm.assert_index_equal(result, expected)

        # intersection of non-overlapping values based on start value and gcd
        index = RangeIndex(1, 10, 2)
        other = RangeIndex(0, 10, 4)
        result = index.intersection(other)
        expected = RangeIndex(0, 0, 1)
        tm.assert_index_equal(result, expected)

    def test_union_noncomparable(self):
        from datetime import datetime, timedelta
        # corner case, non-Int64Index
        now = datetime.now()
        other = Index([now + timedelta(i) for i in range(4)], dtype=object)
        result = self.index.union(other)
        expected = Index(np.concatenate((self.index, other)))
        tm.assert_index_equal(result, expected)

        result = other.union(self.index)
        expected = Index(np.concatenate((other, self.index)))
        tm.assert_index_equal(result, expected)

    def test_union(self):
        RI = RangeIndex
        I64 = Int64Index
        cases = [(RI(0, 10, 1), RI(0, 10, 1), RI(0, 10, 1)),
                 (RI(0, 10, 1), RI(5, 20, 1), RI(0, 20, 1)),
                 (RI(0, 10, 1), RI(10, 20, 1), RI(0, 20, 1)),
                 (RI(0, -10, -1), RI(0, -10, -1), RI(0, -10, -1)),
                 (RI(0, -10, -1), RI(-10, -20, -1), RI(-19, 1, 1)),
                 (RI(0, 10, 2), RI(1, 10, 2), RI(0, 10, 1)),
                 (RI(0, 11, 2), RI(1, 12, 2), RI(0, 12, 1)),
                 (RI(0, 21, 4), RI(-2, 24, 4), RI(-2, 24, 2)),
                 (RI(0, -20, -2), RI(-1, -21, -2), RI(-19, 1, 1)),
                 (RI(0, 100, 5), RI(0, 100, 20), RI(0, 100, 5)),
                 (RI(0, -100, -5), RI(5, -100, -20), RI(-95, 10, 5)),
                 (RI(0, -11, -1), RI(1, -12, -4), RI(-11, 2, 1)),
                 (RI(0), RI(0), RI(0)),
                 (RI(0, -10, -2), RI(0), RI(0, -10, -2)),
                 (RI(0, 100, 2), RI(100, 150, 200), RI(0, 102, 2)),
                 (RI(0, -100, -2), RI(-100, 50, 102), RI(-100, 4, 2)),
                 (RI(0, -100, -1), RI(0, -50, -3), RI(-99, 1, 1)),
                 (RI(0, 1, 1), RI(5, 6, 10), RI(0, 6, 5)),
                 (RI(0, 10, 5), RI(-5, -6, -20), RI(-5, 10, 5)),
                 (RI(0, 3, 1), RI(4, 5, 1), I64([0, 1, 2, 4])),
                 (RI(0, 10, 1), I64([]), RI(0, 10, 1)),
                 (RI(0), I64([1, 5, 6]), I64([1, 5, 6]))]
        for idx1, idx2, expected in cases:
            res1 = idx1.union(idx2)
            res2 = idx2.union(idx1)
            res3 = idx1._int64index.union(idx2)
            tm.assert_index_equal(res1, expected, exact=True)
            tm.assert_index_equal(res2, expected, exact=True)
            tm.assert_index_equal(res3, expected)

    def test_nbytes(self):

        # memory savings vs int index
        i = RangeIndex(0, 1000)
        assert i.nbytes < i._int64index.nbytes / 10

        # constant memory usage
        i2 = RangeIndex(0, 10)
        assert i.nbytes == i2.nbytes

    def test_cant_or_shouldnt_cast(self):
        # can't
        pytest.raises(TypeError, RangeIndex, 'foo', 'bar', 'baz')

        # shouldn't
        pytest.raises(TypeError, RangeIndex, '0', '1', '2')

    def test_view_Index(self):
        self.index.view(Index)

    def test_prevent_casting(self):
        result = self.index.astype('O')
        assert result.dtype == np.object_

    def test_take_preserve_name(self):
        index = RangeIndex(1, 5, name='foo')
        taken = index.take([3, 0, 1])
        assert index.name == taken.name

    def test_take_fill_value(self):
        # GH 12631
        idx = pd.RangeIndex(1, 4, name='xxx')
        result = idx.take(np.array([1, 0, -1]))
        expected = pd.Int64Index([2, 1, 3], name='xxx')
        tm.assert_index_equal(result, expected)

        # fill_value
        msg = "Unable to fill values because RangeIndex cannot contain NA"
        with tm.assert_raises_regex(ValueError, msg):
            idx.take(np.array([1, 0, -1]), fill_value=True)

        # allow_fill=False
        result = idx.take(np.array([1, 0, -1]), allow_fill=False,
                          fill_value=True)
        expected = pd.Int64Index([2, 1, 3], name='xxx')
        tm.assert_index_equal(result, expected)

        msg = "Unable to fill values because RangeIndex cannot contain NA"
        with tm.assert_raises_regex(ValueError, msg):
            idx.take(np.array([1, 0, -2]), fill_value=True)
        with tm.assert_raises_regex(ValueError, msg):
            idx.take(np.array([1, 0, -5]), fill_value=True)

        with pytest.raises(IndexError):
            idx.take(np.array([1, -5]))

    def test_print_unicode_columns(self):
        df = pd.DataFrame({u("\u05d0"): [1, 2, 3],
                           "\u05d1": [4, 5, 6],
                           "c": [7, 8, 9]})
        repr(df.columns)  # should not raise UnicodeDecodeError

    def test_repr_roundtrip(self):
        tm.assert_index_equal(eval(repr(self.index)), self.index)

    def test_slice_keep_name(self):
        idx = RangeIndex(1, 2, name='asdf')
        assert idx.name == idx[1:].name

    def test_explicit_conversions(self):

        # GH 8608
        # add/sub are overridden explicitly for Float/Int Index
        idx = RangeIndex(5)

        # float conversions
        arr = np.arange(5, dtype='int64') * 3.2
        expected = Float64Index(arr)
        fidx = idx * 3.2
        tm.assert_index_equal(fidx, expected)
        fidx = 3.2 * idx
        tm.assert_index_equal(fidx, expected)

        # interops with numpy arrays
        expected = Float64Index(arr)
        a = np.zeros(5, dtype='float64')
        result = fidx - a
        tm.assert_index_equal(result, expected)

        expected = Float64Index(-arr)
        a = np.zeros(5, dtype='float64')
        result = a - fidx
        tm.assert_index_equal(result, expected)

    def test_has_duplicates(self):
        for ind in self.indices:
            if not len(ind):
                continue
            idx = self.indices[ind]
            assert idx.is_unique
            assert not idx.has_duplicates

    def test_ufunc_compat(self):
        idx = RangeIndex(5)
        result = np.sin(idx)
        expected = Float64Index(np.sin(np.arange(5, dtype='int64')))
        tm.assert_index_equal(result, expected)

    def test_extended_gcd(self):
        result = self.index._extended_gcd(6, 10)
        assert result[0] == result[1] * 6 + result[2] * 10
        assert 2 == result[0]

        result = self.index._extended_gcd(10, 6)
        assert 2 == result[1] * 10 + result[2] * 6
        assert 2 == result[0]

    def test_min_fitting_element(self):
        result = RangeIndex(0, 20, 2)._min_fitting_element(1)
        assert 2 == result

        result = RangeIndex(1, 6)._min_fitting_element(1)
        assert 1 == result

        result = RangeIndex(18, -2, -2)._min_fitting_element(1)
        assert 2 == result

        result = RangeIndex(5, 0, -1)._min_fitting_element(1)
        assert 1 == result

        big_num = 500000000000000000000000

        result = RangeIndex(5, big_num * 2, 1)._min_fitting_element(big_num)
        assert big_num == result

    def test_max_fitting_element(self):
        result = RangeIndex(0, 20, 2)._max_fitting_element(17)
        assert 16 == result

        result = RangeIndex(1, 6)._max_fitting_element(4)
        assert 4 == result

        result = RangeIndex(18, -2, -2)._max_fitting_element(17)
        assert 16 == result

        result = RangeIndex(5, 0, -1)._max_fitting_element(4)
        assert 4 == result

        big_num = 500000000000000000000000

        result = RangeIndex(5, big_num * 2, 1)._max_fitting_element(big_num)
        assert big_num == result

    def test_pickle_compat_construction(self):
        # RangeIndex() is a valid constructor
        pass

    def test_slice_specialised(self):

        # scalar indexing
        res = self.index[1]
        expected = 2
        assert res == expected

        res = self.index[-1]
        expected = 18
        assert res == expected

        # slicing
        # slice value completion
        index = self.index[:]
        expected = self.index
        tm.assert_index_equal(index, expected)

        # positive slice values
        index = self.index[7:10:2]
        expected = Index(np.array([14, 18]), name='foo')
        tm.assert_index_equal(index, expected)

        # negative slice values
        index = self.index[-1:-5:-2]
        expected = Index(np.array([18, 14]), name='foo')
        tm.assert_index_equal(index, expected)

        # stop overshoot
        index = self.index[2:100:4]
        expected = Index(np.array([4, 12]), name='foo')
        tm.assert_index_equal(index, expected)

        # reverse
        index = self.index[::-1]
        expected = Index(self.index.values[::-1], name='foo')
        tm.assert_index_equal(index, expected)

        index = self.index[-8::-1]
        expected = Index(np.array([4, 2, 0]), name='foo')
        tm.assert_index_equal(index, expected)

        index = self.index[-40::-1]
        expected = Index(np.array([], dtype=np.int64), name='foo')
        tm.assert_index_equal(index, expected)

        index = self.index[40::-1]
        expected = Index(self.index.values[40::-1], name='foo')
        tm.assert_index_equal(index, expected)

        index = self.index[10::-1]
        expected = Index(self.index.values[::-1], name='foo')
        tm.assert_index_equal(index, expected)

    def test_len_specialised(self):

        # make sure that our len is the same as
        # np.arange calc

        for step in np.arange(1, 6, 1):

            arr = np.arange(0, 5, step)
            i = RangeIndex(0, 5, step)
            assert len(i) == len(arr)

            i = RangeIndex(5, 0, step)
            assert len(i) == 0

        for step in np.arange(-6, -1, 1):

            arr = np.arange(5, 0, step)
            i = RangeIndex(5, 0, step)
            assert len(i) == len(arr)

            i = RangeIndex(0, 5, step)
            assert len(i) == 0

    def test_append(self):
        # GH16212
        RI = RangeIndex
        I64 = Int64Index
        F64 = Float64Index
        OI = Index
        cases = [([RI(1, 12, 5)], RI(1, 12, 5)),
                 ([RI(0, 6, 4)], RI(0, 6, 4)),
                 ([RI(1, 3), RI(3, 7)], RI(1, 7)),
                 ([RI(1, 5, 2), RI(5, 6)], RI(1, 6, 2)),
                 ([RI(1, 3, 2), RI(4, 7, 3)], RI(1, 7, 3)),
                 ([RI(-4, 3, 2), RI(4, 7, 2)], RI(-4, 7, 2)),
                 ([RI(-4, -8), RI(-8, -12)], RI(0, 0)),
                 ([RI(-4, -8), RI(3, -4)], RI(0, 0)),
                 ([RI(-4, -8), RI(3, 5)], RI(3, 5)),
                 ([RI(-4, -2), RI(3, 5)], I64([-4, -3, 3, 4])),
                 ([RI(-2,), RI(3, 5)], RI(3, 5)),
                 ([RI(2,), RI(2)], I64([0, 1, 0, 1])),
                 ([RI(2,), RI(2, 5), RI(5, 8, 4)], RI(0, 6)),
                 ([RI(2,), RI(3, 5), RI(5, 8, 4)], I64([0, 1, 3, 4, 5])),
                 ([RI(-2, 2), RI(2, 5), RI(5, 8, 4)], RI(-2, 6)),
                 ([RI(3,), I64([-1, 3, 15])], I64([0, 1, 2, -1, 3, 15])),
                 ([RI(3,), F64([-1, 3.1, 15.])], F64([0, 1, 2, -1, 3.1, 15.])),
                 ([RI(3,), OI(['a', None, 14])], OI([0, 1, 2, 'a', None, 14])),
                 ([RI(3, 1), OI(['a', None, 14])], OI(['a', None, 14]))
                 ]

        for indices, expected in cases:
            result = indices[0].append(indices[1:])
            tm.assert_index_equal(result, expected, exact=True)

            if len(indices) == 2:
                # Append single item rather than list
                result2 = indices[0].append(indices[1])
                tm.assert_index_equal(result2, expected, exact=True)

    @pytest.mark.parametrize('start,stop,step',
                             [(0, 400, 3), (500, 0, -6), (-10**6, 10**6, 4),
                              (10**6, -10**6, -4), (0, 10, 20)])
    def test_max_min(self, start, stop, step):
        # GH17607
        idx = RangeIndex(start, stop, step)
        expected = idx._int64index.max()
        result = idx.max()
        assert result == expected

        expected = idx._int64index.min()
        result = idx.min()
        assert result == expected

        # empty
        idx = RangeIndex(start, stop, -step)
        assert isna(idx.max())
        assert isna(idx.min())