Description
Pandas version checks
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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
pd.DataFrame(
{
"a": [1, 2, None]
},
dtype="Int64"
).astype(str).astype("Int64")Issue Description
When casting an Int64 NA-Value to a string it returns <NA> which is not well interpretable as a missing value for anything. It even fails in converting it back to an Int64 value.
Expected Behavior
Int64 NA-Values should be casted to None when casted to String, as this is the equivalent represantation in a string-column, similar to being convertet to a float NaN for float, which is also shown by the following example, which works:
import pandas as pd
pd.DataFrame(
{
"a": [1, 2, None]
},
dtype="Int64"
).astype(str).replace("<NA>", None).astype("Int64")
Installed Versions
INSTALLED VERSIONS
commit : bdc79c1
python : 3.10.12.final.0
python-bits : 64
OS : Linux
OS-release : 6.8.0-47-generic
Version : #47~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Oct 2 16:16:55 UTC 2
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : en_US.UTF-8
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 2.2.1
numpy : 1.26.4
pytz : 2024.1
dateutil : 2.9.0.post0
setuptools : 69.0.3
pip : 24.0
Cython : None
pytest : 8.2.2
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.3
IPython : 8.22.2
pandas_datareader : None
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.12.3
bottleneck : None
dataframe-api-compat : None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : 3.1.5
pandas_gbq : None
pyarrow : 15.0.2
pyreadstat : None
python-calamine : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : 2.0.28
tables : None
tabulate : None
xarray : None
xlrd : None
zstandard : None
tzdata : 2024.1
qtpy : None
pyqt5 : None