BUG: idxmax and idxmin with skipna=False raise NotImplementedError

[sfc-gh-mvashishtha]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd
import pytest

with pytest.raises(NotImplementedError):
  pd.DataFrame([pd.Timedelta(1), None]).idxmax(skipna=False, axis=0)

with pytest.raises(NotImplementedError):
  pd.DataFrame([pd.Timedelta(1), None]).idxmax(skipna=False, axis=1)

with pytest.raises(NotImplementedError):
  pd.DataFrame([pd.Timedelta(1), None]).idxmin(skipna=False, axis=0)

with pytest.raises(NotImplementedError):
  pd.DataFrame([pd.Timedelta(1), None]).idxmin(skipna=False, axis=1)

Issue Description

idxmax and idxmin with skipna=False raise NotImplementedError

Expected Behavior

should compute idxmin and idxmax without raising error

Installed Versions

INSTALLED VERSIONS
------------------
commit                : d9cdd2ee5a58015ef6f4d15c7226110c9aab8140
python                : 3.9.18.final.0
python-bits           : 64
OS                    : Darwin
OS-release            : 23.6.0
Version               : Darwin Kernel Version 23.6.0: Mon Jul 29 21:13:04 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T6020
machine               : arm64
processor             : arm
byteorder             : little
LC_ALL                : None
LANG                  : en_US.UTF-8
LOCALE                : en_US.UTF-8

pandas                : 2.2.2
numpy                 : 1.26.3
pytz                  : 2023.3.post1
dateutil              : 2.8.2
setuptools            : 68.2.2
pip                   : 23.3.1
Cython                : None
pytest                : 8.3.2
hypothesis            : None
sphinx                : None
blosc                 : None
feather               : None
xlsxwriter            : None
lxml.etree            : None
html5lib              : None
pymysql               : None
psycopg2              : None
jinja2                : None
IPython               : 8.18.1
pandas_datareader     : None
adbc-driver-postgresql: None
adbc-driver-sqlite    : None
bs4                   : None
bottleneck            : None
dataframe-api-compat  : None
fastparquet           : None
fsspec                : None
gcsfs                 : None
matplotlib            : None
numba                 : None
numexpr               : None
odfpy                 : None
openpyxl              : None
pandas_gbq            : None
pyarrow               : None
pyreadstat            : None
python-calamine       : None
pyxlsb                : None
s3fs                  : None
scipy                 : None
sqlalchemy            : None
tables                : None
tabulate              : None
xarray                : None
xlrd                  : None
zstandard             : None
tzdata                : 2023.4
qtpy                  : None
pyqt5                 : None

[natmokval]

Thank you @sfc-gh-mvashishtha for reporting this. This behavior is fixed on the main branch. The expected behavior for your example is to raise a ValueError: Encountered an NA value with skipna=False.

According to the documentation of these methods pandas.DataFrame.idxmin

If the entire Series is NA, or if skipna=False and there is an NA value, this method will raise a ValueError.

[natmokval]

closed due to fixing this behaviour on the main branch