Skip to content

BUG: is_string_dtype(pd.Index([], dtype='O')) returns False #54661

Closed
@flying-sheep

Description

@flying-sheep

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
from pandas.api.types import is_string_dtype

assert is_string_dtype(pd.Index([], dtype='O'))

Issue Description

For object arrays it tests if all objects are strings. That test should be successful when 0 items are tested.

Expected Behavior

The assertion succeeds.

Installed Versions

INSTALLED VERSIONS

commit : 6e194cf
python : 3.10.12.final.0
python-bits : 64
OS : Linux
OS-release : 6.4.10-zen2-1-zen
Version : #1 ZEN SMP PREEMPT_DYNAMIC Sun, 13 Aug 2023 01:33:59 +0000
machine : x86_64
processor :
byteorder : little
LC_ALL : None
LANG : de_DE.UTF-8
LOCALE : de_DE.UTF-8

pandas : 2.1.0rc0
numpy : 1.24.4
pytz : 2023.3
dateutil : 2.8.2
setuptools : 68.1.0
pip : 23.2.1
Cython : None
pytest : 7.4.0
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.2
IPython : None
pandas_datareader : None
bs4 : None
bottleneck : None
brotli : None
dataframe-api-compat: None
fastparquet : None
fsspec : 2023.6.0
gcsfs : None
matplotlib : 3.7.2
numba : 0.57.1
numexpr : None
odfpy : None
openpyxl : 3.1.2
pandas_gbq : None
pyarrow : None
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.11.2
snappy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None

Metadata

Metadata

Assignees

No one assigned

    Labels

    BugDtype ConversionsUnexpected or buggy dtype conversionsStringsString extension data type and string data

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions