"""
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Tests involving custom Index subclasses
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"""
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import numpy as np
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|
from pandas import (
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DataFrame,
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Index,
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)
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import pandas._testing as tm
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|
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class CustomIndex(Index):
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def __new__(cls, data, name=None):
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# assert that this index class cannot hold strings
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if any(isinstance(val, str) for val in data):
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raise TypeError("CustomIndex cannot hold strings")
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if name is None and hasattr(data, "name"):
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name = data.name
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data = np.array(data, dtype="O")
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return cls._simple_new(data, name)
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|
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def test_insert_fallback_to_base_index():
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# https://github.com/pandas-dev/pandas/issues/47071
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idx = CustomIndex([1, 2, 3])
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result = idx.insert(0, "string")
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expected = Index(["string", 1, 2, 3], dtype=object)
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tm.assert_index_equal(result, expected)
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df = DataFrame(
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np.random.randn(2, 3), columns=idx, index=Index([1, 2], name="string")
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)
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result = df.reset_index()
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tm.assert_index_equal(result.columns, expected)
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