BUG: TypeError on Series(dtype='string').value_counts().idxmax() (original) (raw)

Expected output

Obtain the most frequent string in a series:

pd.Series('a').value_counts().idxmax()
'a'

Problem

Changing the dtype on the second example from 'object' to 'string' breaks this idiom:

pd.Series('a', dtype='string').value_counts().idxmax() Traceback (most recent call last): File "", line 1, in File "pandas/core/series.py", line 2168, in idxmax i = nanops.nanargmax(self._values, skipna=skipna) File "pandas/core/nanops.py", line 71, in _f return f(*args, **kwargs) File "pandas/core/nanops.py", line 924, in nanargmax result = values.argmax(axis) TypeError: argmax() takes 1 positional argument but 2 were given

The problem is evidently not due to a 'string' index:

pd.Series([1], index=pd.Series(['a'], dtype='string')).idxmax() 'a'

Output of pd.show_versions()

Details

>>> pd.show_versions()

INSTALLED VERSIONS
------------------
commit           : 2a7d3326dee660824a8433ffd01065f8ac37f7d6
python           : 3.7.9.final.0
python-bits      : 64
OS               : Darwin
OS-release       : 19.6.0
Version          : Darwin Kernel Version 19.6.0: Thu Jun 18 20:49:00 PDT 2020; root:xnu-6153.141.1~1/RELEASE_X86_64
machine          : x86_64
processor        : i386
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : en_US.UTF-8

pandas           : 1.1.2
numpy            : 1.19.2
pytz             : 2020.1
dateutil         : 2.8.1
pip              : 20.1.1
setuptools       : 47.1.0
Cython           : None
pytest           : None
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
fsspec           : None
fastparquet      : None
gcsfs            : None
matplotlib       : None
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pytables         : None
pyxlsb           : None
s3fs             : None
scipy            : 1.5.2
sqlalchemy       : None
tables           : None
tabulate         : None
xarray           : None
xlrd             : None
xlwt             : None
numba            : None