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BUG: .str.split() fails with pyarrow strings #56271

@mattharrison

Description

@mattharrison

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  • 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 io data = '''name,x,y matt b,10,20 fred c,20,1 jeff d,2,3 lisa e,5,7 adam f,23,1''' df = pd.read_csv(io.StringIO(data), engine='pyarrow', dtype_backend='pyarrow') df.name.str.split()

Issue Description

In Pandas 1, you could split with no parameters (like python does with 'matt h'.split(). This doesn't work with pyarrow types.

It gives a TypeError:

--------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In[47], line 12 4 data = '''name,x,y 5 matt a,10,20 6 fred b,20,1 7 jeff c,2,3 8 lisa d,5,7 9 adam e,23,1''' 11 df = pd.read_csv(io.StringIO(data), engine='pyarrow', dtype_backend='pyarrow') ---> 12 df.name.str.split() File ~/.envs/menv/lib/python3.10/site-packages/pandas/core/strings/accessor.py:136, in forbid_nonstring_types.<locals>._forbid_nonstring_types.<locals>.wrapper(self, *args, **kwargs) 131 msg = ( 132 f"Cannot use .str.{func_name} with values of " 133 f"inferred dtype '{self._inferred_dtype}'." 134 ) 135 raise TypeError(msg) --> 136 return func(self, *args, **kwargs) File ~/.envs/menv/lib/python3.10/site-packages/pandas/core/strings/accessor.py:915, in StringMethods.split(self, pat, n, expand, regex) 913 if is_re(pat): 914 regex = True --> 915 result = self._data.array._str_split(pat, n, expand, regex) 916 return self._wrap_result(result, returns_string=expand, expand=expand) File ~/.envs/menv/lib/python3.10/site-packages/pandas/core/arrays/arrow/array.py:2273, in ArrowExtensionArray._str_split(self, pat, n, expand, regex) 2271 else: 2272 split_func = pc.split_pattern -> 2273 return type(self)(split_func(self._pa_array, pat, max_splits=n)) File ~/.envs/menv/lib/python3.10/site-packages/pyarrow/compute.py:258, in _make_generic_wrapper.<locals>.wrapper(memory_pool, options, *args, **kwargs) 256 else: 257 option_args = () --> 258 options = _handle_options(func_name, options_class, options, 259 option_args, kwargs) 260 if args and isinstance(args[0], Expression): 261 return Expression._call(func_name, list(args), options) File ~/.envs/menv/lib/python3.10/site-packages/pyarrow/compute.py:221, in _handle_options(name, options_class, options, args, kwargs) 216 if options is not None: 217 raise TypeError( 218 "Function {!r} called with both an 'options' argument " 219 "and additional arguments" 220 .format(name)) --> 221 return options_class(*args, **kwargs) 223 if options is not None: 224 if isinstance(options, dict): File ~/.envs/menv/lib/python3.10/site-packages/pyarrow/_compute.pyx:1894, in pyarrow._compute.SplitPatternOptions.__init__() File ~/.envs/menv/lib/python3.10/site-packages/pyarrow/_compute.pyx:1872, in pyarrow._compute._SplitPatternOptions._set_options() File stringsource:15, in string.from_py.__pyx_convert_string_from_py_std__in_string() TypeError: expected bytes, NoneType found 

Expected Behavior

I expect Pandas 1 behavior.

Installed Versions

INSTALLED VERSIONS

commit : e86ed37
python : 3.10.13.final.0
python-bits : 64
OS : Darwin
OS-release : 21.6.0
Version : Darwin Kernel Version 21.6.0: Wed Aug 10 14:28:23 PDT 2022; root:xnu-8020.141.5~2/RELEASE_ARM64_T6000
machine : arm64
processor : arm
byteorder : little
LC_ALL : en_US.UTF-8
LANG : None
LOCALE : en_US.UTF-8

pandas : 2.1.1
numpy : 1.23.5
pytz : 2023.3
dateutil : 2.8.2
setuptools : 67.6.1
pip : 23.2.1
Cython : 3.0.4
pytest : 7.2.0
hypothesis : 6.81.2
sphinx : None
blosc : None
feather : None
xlsxwriter : 3.1.2
lxml.etree : 4.9.2
html5lib : 1.1
pymysql : None
psycopg2 : None
jinja2 : 3.1.2
IPython : 8.8.0
pandas_datareader : None
bs4 : 4.11.1
bottleneck : None
dataframe-api-compat: None
fastparquet : None
fsspec : 2023.3.0
gcsfs : None
matplotlib : 3.6.2
numba : 0.56.4
numexpr : 2.8.4
odfpy : None
openpyxl : 3.0.10
pandas_gbq : None
pyarrow : 13.0.0
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.10.0
sqlalchemy : 2.0.21
tables : None
tabulate : 0.9.0
xarray : None
xlrd : 2.0.1
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None

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