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