Dataframe replace empty string casts Int64 columns to float

[miroli]

Code Sample

df = pd.DataFrame({
    'a': [1, 2, 3, np.nan], 
    'b': ['some', 'strings', 'here', 'he']
})

df['a'] = df['a'].astype('Int64')

df.replace('', np.nan).dtypes  # Column a is now float

Problem description

The new Int64Dtype does not behave as expected here. If you do a global replacement of empty strings to NaN's, it seems weird that this would have the side effect of casting ints to floats.

Expected Output

Expected:

a     Int64
b    object
dtype: object

Output of pd.show_versions()

INSTALLED VERSIONS

commit: None
python: 3.6.5.final.0
python-bits: 64
OS: Darwin
OS-release: 18.0.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.24.1
pytest: None
pip: 10.0.1
setuptools: 39.2.0
Cython: None
numpy: 1.16.1
scipy: 1.2.1
pyarrow: None
xarray: None
IPython: 7.2.0
sphinx: None
patsy: None
dateutil: 2.8.0
pytz: 2018.9
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 3.0.2
openpyxl: 2.4.11
xlrd: 1.2.0
xlwt: None
xlsxwriter: None
lxml.etree: None
bs4: None
html5lib: 1.0.1
sqlalchemy: 1.2.12
pymysql: None
psycopg2: 2.7.5 (dt dec pq3 ext lo64)
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
gcsfs: None

[jreback]

since this is an optional dtype currently there are number of edge cases - welcome a PR to fix this

[TomAugspurger]

I think we have other issues about replace on extension arrays. Can you search for them and close this issue if you find a duplicate?

…

On Mon, Feb 25, 2019 at 4:50 AM Robin Linderborg ***@***.***> wrote: Code Sample df = pd.DataFrame({ 'a': [1, 2, 3, np.nan], 'b': ['some', 'strings', 'here', 'he'] }) df['a'] = df['a'].astype('Int64') df.replace('', np.nan).dtypes # Column a is now float Problem description The new Int64Dtype does not behave as expected here. If you do a global replacement of empty strings to NaN's, it seems weird that this would have the side effect of casting ints to floats. Expected Output Expected: a Int64 b object dtype: object Output of pd.show_versions() INSTALLED VERSIONS commit: None python: 3.6.5.final.0 python-bits: 64 OS: Darwin OS-release: 18.0.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: en_US.UTF-8 LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 pandas: 0.24.1 pytest: None pip: 10.0.1 setuptools: 39.2.0 Cython: None numpy: 1.16.1 scipy: 1.2.1 pyarrow: None xarray: None IPython: 7.2.0 sphinx: None patsy: None dateutil: 2.8.0 pytz: 2018.9 blosc: None bottleneck: None tables: None numexpr: None feather: None matplotlib: 3.0.2 openpyxl: 2.4.11 xlrd: 1.2.0 xlwt: None xlsxwriter: None lxml.etree: None bs4: None html5lib: 1.0.1 sqlalchemy: 1.2.12 pymysql: None psycopg2: 2.7.5 (dt dec pq3 ext lo64) jinja2: 2.10 s3fs: None fastparquet: None pandas_gbq: None pandas_datareader: None gcsfs: None — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#25438>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABQHItF6yB6FwAcXKZJ44C5qvuqcbeAYks5vQ7_3gaJpZM4bPmHX> .