BUG: .dt.isocalendar().week returns unexpected dtype (UInt32)

[outa]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• (optional) I have confirmed this bug exists on the master branch of pandas.

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Note: Please read this guide detailing how to provide the necessary information for us to reproduce your bug.

Code Sample, a copy-pastable example

data = {'date': pd.date_range('2021-07-01', freq='D', periods=7)}
df = pd.DataFrame(data)

weeknumbers = df.date.dt.isocalendar().week

weeknumbers
0    26
1    26
2    26
3    26
4    27
5    27
6    27
Name: week, dtype: UInt32

Problem description

This returns dtype UInt32, with weeknumbers.values being an "IntegerArray" from pandas.

I am not sure if this is intended, but I discovered this because I replaced the deprecated dt.weekofyear with dt.isocalendar().week and then had weeknumbers.values.tolist() at a later point in my code which results in an AttributeError.

Expected Output

I would have expected the dtype to be int64, or, more importanty, the the .values being a numpy array, so that .values.tolist() works as expected.

Output of pd.show_versions()

INSTALLED VERSIONS

commit : f00ed8f
python : 3.9.5.final.0
python-bits : 64
OS : Linux
OS-release : 5.8.0-59-generic
Version : #66-Ubuntu SMP Thu Jun 17 00:46:01 UTC 2021
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : de_DE.UTF-8
LOCALE : de_DE.UTF-8

pandas : 1.3.0
numpy : 1.21.0
pytz : 2021.1
dateutil : 2.8.1
pip : 21.1.3
setuptools : 52.0.0.post20210125
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
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
numba : None

[rhshadrach]

This was indeed intentional, e.g #33220 (comment). As with any pandas Series, you can directly call tolist without accessing the underlying array:

df.date.dt.isocalendar().week.tolist()

Does this satisfy your use-case?

[outa]

Yes it does. Thanks for the clarification!