code: import numpy as np
  import pytest
  
  from pandas.core.dtypes.common import ensure_platform_int
  
  import pandas as pd
  from pandas import (
      Float64Index,
      Index,
      Int64Index,
      RangeIndex,
  )
  import pandas._testing as tm
  from pandas.tests.indexes.test_numeric import Numeric
  
  # aliases to make some tests easier to read
  RI = RangeIndex
  I64 = Int64Index
  F64 = Float64Index
  OI = Index
  
  
  class TestRangeIndex(Numeric):
      _index_cls = RangeIndex
  
      @pytest.fixture
      def simple_index(self) -> Index:
          return self._index_cls(start=0, stop=20, step=2)
  
      @pytest.fixture(
          params=[
              RangeIndex(start=0, stop=20, step=2, name="foo"),
              RangeIndex(start=18, stop=-1, step=-2, name="bar"),
          ],
          ids=["index_inc", "index_dec"],
      )
      def index(self, request):
          return request.param
  
      def test_can_hold_identifiers(self, simple_index):
          idx = simple_index
          key = idx[0]
          assert idx._can_hold_identifiers_and_holds_name(key) is False
  
      def test_too_many_names(self, simple_index):
          index = simple_index
          with pytest.raises(ValueError, match="^Length"):
              index.names = ["roger", "harold"]
  
      @pytest.mark.parametrize(
          "index, start, stop, step",
          [
              (RangeIndex(5), 0, 5, 1),
              (RangeIndex(0, 5), 0, 5, 1),
              (RangeIndex(5, step=2), 0, 5, 2),
              (RangeIndex(1, 5, 2), 1, 5, 2),
          ],
      )
      def test_start_stop_step_attrs(self, index, start, stop, step):
          # GH 25710
          assert index.start == start
          assert index.stop == stop
          assert index.step == step
  
      @pytest.mark.parametrize("attr_name", ["_start", "_stop", "_step"])
      def test_deprecated_start_stop_step_attrs(self, attr_name, simple_index):
          # GH 26581
          idx = simple_index
          with tm.assert_produces_warning(FutureWarning):
              getattr(idx, attr_name)
  
      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._range == range(0, 5, 1)
          assert i_copy.name == "Foo"
  
      def test_repr(self):
          i = RangeIndex(5, name="Foo")
          result = repr(i)
          expected = "RangeIndex(start=0, stop=5, step=1, name='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, None, pd.NA]:
              result = RangeIndex(5).insert(1, na)
              tm.assert_index_equal(result, expected)
  
          result = RangeIndex(5).insert(1, pd.NaT)
          expected = Index([0, pd.NaT, 1, 2, 3, 4], dtype=object)
          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
  
          msg = "index 5 is out of bounds for axis 0 with size 5"
          with pytest.raises((IndexError, ValueError), match=msg):
              # either depending on numpy version
              result = idx.delete(len(idx))
  
      def test_view(self):
          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, simple_index):
          index = simple_index
          assert index.dtype == np.int64
  
      def test_cache(self):
          # GH 26565, GH26617, GH35432
          # This test checks whether _cache has been set.
          # Calling RangeIndex._cache["_data"] creates an int64 array of the same length
          # as the RangeIndex and stores it in _cache.
          idx = RangeIndex(0, 100, 10)
  
          assert idx._cache == {}
  
          repr(idx)
          assert idx._cache == {}
  
          str(idx)
          assert idx._cache == {}
  
          idx.get_loc(20)
          assert idx._cache == {}
  
          90 in idx  # True
          assert idx._cache == {}
  
          91 in idx  # False
          assert idx._cache == {}
  
          idx.all()
          assert idx._cache == {}
  
          idx.any()
          assert idx._cache == {}
  
          for _ in idx:
              pass
          assert idx._cache == {}
  
          idx.format()
          assert idx._cache == {}
  
          df = pd.DataFrame({"a": range(10)}, index=idx)
  
          str(df)
          assert idx._cache == {}
  
          df.loc[50]
          assert idx._cache == {}
  
          with pytest.raises(KeyError, match="51"):
              df.loc[51]
          assert idx._cache == {}
  
          df.loc[10:50]
          assert idx._cache == {}
  
          df.iloc[5:10]
          assert idx._cache == {}
  
          # idx._cache should contain a _data entry after call to idx._data
          idx._data
          assert isinstance(idx._data, np.ndarray)
          assert idx._data is idx._data  # check cached value is reused
          assert len(idx._cache) == 1
          expected = np.arange(0, 100, 10, dtype="int64")
          tm.assert_numpy_array_equal(idx._cache["_data"], expected)
  
      def test_is_monotonic(self):
          index = RangeIndex(0, 20, 2)
          assert index.is_monotonic is True
          assert index.is_monotonic_increasing is True
          assert index.is_monotonic_decreasing is False
          assert index._is_strictly_monotonic_increasing is True
          assert 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, simple_index):
          idx = simple_index
          assert idx.all() == idx.values.all()
          assert idx.any() == idx.values.any()
  
      def test_identical(self, simple_index):
          index = simple_index
          i = Index(index.copy())
          assert i.identical(index)
  
          # we don't allow object dtype for RangeIndex
          if isinstance(index, RangeIndex):
              return
  
          same_values_different_type = Index(i, dtype=object)
          assert not i.identical(same_values_different_type)
  
          i = index.copy(dtype=object)
          i = i.rename("foo")
          same_values = Index(i, dtype=object)
          assert same_values.identical(index.copy(dtype=object))
  
          assert not i.identical(index)
          assert Index(same_values, name="foo", dtype=object).identical(i)
  
          assert not index.copy(dtype=object).identical(index.copy(dtype="int64"))
  
      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
  
      @pytest.mark.parametrize(
          "start,stop,step",
          [
              # can't
              ("foo", "bar", "baz"),
              # shouldn't
              ("0", "1", "2"),
          ],
      )
      def test_cant_or_shouldnt_cast(self, start, stop, step):
          msg = f"Wrong type {type(start)} for value {start}"
          with pytest.raises(TypeError, match=msg):
              RangeIndex(start, stop, step)
  
      def test_view_index(self, simple_index):
          index = simple_index
          index.view(Index)
  
      def test_prevent_casting(self, simple_index):
          index = simple_index
          result = index.astype("O")
          assert result.dtype == np.object_
  
      def test_repr_roundtrip(self, simple_index):
          index = simple_index
          tm.assert_index_equal(eval(repr(index)), index)
  
      def test_slice_keep_name(self):
          idx = RangeIndex(1, 2, name="asdf")
          assert idx.name == idx[1:].name
  
      def test_has_duplicates(self, index):
          assert index.is_unique
          assert not index.has_duplicates
  
      def test_extended_gcd(self, simple_index):
          index = simple_index
          result = index._extended_gcd(6, 10)
          assert result[0] == result[1] * 6 + result[2] * 10
          assert 2 == result[0]
  
          result = 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, simple_index):
          index = simple_index
          index.name = "foo"
  
          # scalar indexing
          res = index[1]
          expected = 2
          assert res == expected
  
          res = index[-1]
          expected = 18
          assert res == expected
  
          # slicing
          # slice value completion
          index_slice = index[:]
          expected = index
          tm.assert_index_equal(index_slice, expected)
  
          # positive slice values
          index_slice = index[7:10:2]
          expected = Index(np.array([14, 18]), name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          # negative slice values
          index_slice = index[-1:-5:-2]
          expected = Index(np.array([18, 14]), name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          # stop overshoot
          index_slice = index[2:100:4]
          expected = Index(np.array([4, 12]), name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          # reverse
          index_slice = index[::-1]
          expected = Index(index.values[::-1], name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          index_slice = index[-8::-1]
          expected = Index(np.array([4, 2, 0]), name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          index_slice = index[-40::-1]
          expected = Index(np.array([], dtype=np.int64), name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          index_slice = index[40::-1]
          expected = Index(index.values[40::-1], name="foo")
          tm.assert_index_equal(index_slice, expected)
  
          index_slice = index[10::-1]
          expected = Index(index.values[::-1], name="foo")
          tm.assert_index_equal(index_slice, expected)
  
      @pytest.mark.parametrize("step", set(range(-5, 6)) - {0})
      def test_len_specialised(self, step):
          # make sure that our len is the same as np.arange calc
          start, stop = (0, 5) if step > 0 else (5, 0)
  
          arr = np.arange(start, stop, step)
          index = RangeIndex(start, stop, step)
          assert len(index) == len(arr)
  
          index = RangeIndex(stop, start, step)
          assert len(index) == 0
  
      @pytest.fixture(
          params=[
              ([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, 15.0])], F64([0, 1, 2, -1, 3.1, 15.0])),
              ([RI(3), OI(["a", None, 14])], OI([0, 1, 2, "a", None, 14])),
              ([RI(3, 1), OI(["a", None, 14])], OI(["a", None, 14])),
          ]
      )
      def appends(self, request):
          """Inputs and expected outputs for RangeIndex.append test"""
          return request.param
  
      def test_append(self, appends):
          # GH16212
  
          indices, expected = appends
  
          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)
  
      def test_engineless_lookup(self):
          # GH 16685
          # Standard lookup on RangeIndex should not require the engine to be
          # created
          idx = RangeIndex(2, 10, 3)
  
          assert idx.get_loc(5) == 1
          tm.assert_numpy_array_equal(
              idx.get_indexer([2, 8]), ensure_platform_int(np.array([0, 2]))
          )
          with pytest.raises(KeyError, match="3"):
              idx.get_loc(3)
  
          assert "_engine" not in idx._cache
  
          # Different types of scalars can be excluded immediately, no need to
          #  use the _engine
          with pytest.raises(KeyError, match="'a'"):
              idx.get_loc("a")
  
          assert "_engine" not in idx._cache
  
      def test_format_empty(self):
          # GH35712
          empty_idx = self._index_cls(0)
          assert empty_idx.format() == []
          assert empty_idx.format(name=True) == [""]
  
      @pytest.mark.parametrize(
          "RI",
          [
              RangeIndex(0, -1, -1),
              RangeIndex(0, 1, 1),
              RangeIndex(1, 3, 2),
              RangeIndex(0, -1, -2),
              RangeIndex(-3, -5, -2),
          ],
      )
      def test_append_len_one(self, RI):
          # GH39401
          result = RI.append([])
          tm.assert_index_equal(result, RI, exact=True)
  
      @pytest.mark.parametrize("base", [RangeIndex(0, 2), Index([0, 1])])
      def test_isin_range(self, base):
          # GH#41151
          values = RangeIndex(0, 1)
          result = base.isin(values)
          expected = np.array([True, False])
          tm.assert_numpy_array_equal(result, expected)
  
apis: pandas._testing.assert_numpy_array_equal pandas._testing.assert_produces_warning pandas.Float64Index numpy.arange pandas._testing.assert_index_equal pandas.RangeIndex numpy.array pandas.Index