BUG: FutureWarning for pandas datetime dtype series strftime with all NA values (original) (raw)

Pandas version checks

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Reproducible Example

import pandas as pd

s = pd.Series([pd.NaT], dtype="datetime64[ns]") s.dt.strftime("%Y-%m-%d")

Issue Description

Since Pandas 1.4.0 a warning is raised: FutureWarning: In a future version, the Index constructor will not infer numeric dtypes when passed object-dtype sequences (matching Series behavior)
This warning is raised when all values in the series are N/A (even though the dtype of the series is correct).

Note: the warning is not raised when one of the values in the series is not NA

Expected Behavior

No FutureWarning should be raised.

Installed Versions

Details

INSTALLED VERSIONS

commit : bb1f651
python : 3.9.10.final.0
python-bits : 64
OS : Windows
OS-release : 10
Version : 10.0.19044
machine : AMD64
processor : Intel64 Family 6 Model 85 Stepping 4, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : English_United States.1252
pandas : 1.4.0
numpy : 1.22.2
pytz : 2021.3
dateutil : 2.8.2
pip : 21.3.1
setuptools : 59.2.0
Cython : None
pytest : 7.0.0
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : None
pandas_datareader: None
bs4 : None
bottleneck : None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : 3.0.9
pandas_gbq : None
pyarrow : None
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.7.3
sqlalchemy : 1.4.31
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
zstandard : None