BUG: groupby.first() with None values fills None value with next row #58611
Description
Pandas version checks
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
python
import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon
gdf = pgd.Geopandas([{"ID1": "3991b7ab", "ID2": nan,"geometry": POLYGON ((...)), "area_m": 10720.28326},
{"ID1": "3991b7ab","ID2": "dc4772ed", "geometry": MULTIPOLYGON(((...)), "area": 0.24245}]
gdf.assign(area=lambda x: x.geometry.area).sort_values(by="area", ascending=False).query("FLUR_OBJECT_UUI == '3991b7ab'").groupby(by="ID1").first()Issue Description
I have a (Geo)DataFrame with Multiple UUID columns.
When sorting the rows, the first columns, can have a None value. After groupby if ID1, the None value of ID2 is replaced withe next value in that column.
Expected Behavior
The value of ID2 should be None.
Installed Versions
NSTALLED VERSIONS
commit : d9cdd2e
python : 3.11.8.final.0
python-bits : 64
OS : Windows
OS-release : 10
Version : 10.0.22631
machine : AMD64
processor : Intel64 Family 6 Model 186 Stepping 2, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : de_DE.cp1252
pandas : 2.2.2
numpy : 1.26.3
pytz : 2024.1
dateutil : 2.9.0.post0
setuptools : 69.1.0
pip : 24.0
Cython : None
pytest : 8.2.0
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.3
IPython : 8.23.0
pandas_datareader : None
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.12.3
bottleneck : None
dataframe-api-compat : None
fastparquet : None
fsspec : 2024.3.1
gcsfs : None
matplotlib : None
numba : 0.59.0
numexpr : None
odfpy : None
openpyxl : 3.1.2
pandas_gbq : None
pyarrow : None
pyreadstat : None
python-calamine : None
pyxlsb : None
s3fs : None
scipy : 1.13.0
sqlalchemy : 2.0.30
tables : None
tabulate : None
xarray : 2024.1.1
xlrd : None
zstandard : None
tzdata : 2024.1
qtpy : None
pyqt5 : None