BUG: Series.str.extractall with arrow string returns object dtype · Issue #53846 · pandas-dev/pandas (original) (raw)

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

k = pd.Series(["abc", "ab"], dtype=pd.ArrowDtype(pa.string())) k.str.extractall("(ab)").dtypes 0 object dtype: object

Issue Description

Calling extractall on an arrow string series changes the type from "string[pyarrow]" to object.

Expected Behavior

I would expect a column returned to be typed "string[pyarrow]", not object, or a not implemented error. For reference. Series.str.extract with the arrow string series raises a notimplemented:

`

k.str.extract("(ab)")
Traceback (most recent call last):
File "", line 1, in
File "C:\ca2_ps_311_0515\Lib\site-packages\pandas\core\strings\accessor.py", line 129, in wrapper
return func(self, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\ca2_ps_311_0515\Lib\site-packages\pandas\core\strings\accessor.py", line 2611, in extract
result_list = self._data.array._str_extract(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\ca2_ps_311_0515\Lib\site-packages\pandas\core\arrays\arrow\array.py", line 1959, in _str_extract
raise NotImplementedError(
NotImplementedError: str.extract not supported with pd.ArrowDtype(pa.string()).

`

Installed Versions

pd.show_versions()

INSTALLED VERSIONS

commit : 965ceca
python : 3.11.2.final.0
python-bits : 64
OS : Windows
OS-release : 10
Version : 10.0.22621
machine : AMD64
processor : Intel64 Family 6 Model 85 Stepping 7, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : English_United States.1252

pandas : 2.0.2
numpy : 1.24.3
pytz : 2023.3
dateutil : 2.8.2
setuptools : 67.7.2
pip : 23.1.2
Cython : None
pytest : 7.0.1
hypothesis : None
sphinx : 4.2.0
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.2
IPython : 8.13.2
pandas_datareader: None
bs4 : 4.12.2
bottleneck : None
brotli : None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 12.0.0
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : None
snappy : None
sqlalchemy : None
tables : None
tabulate : 0.8.9
xarray : None
xlrd : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None