BUG: style.format na_rep raises error with list elements #47103
Description
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Reproducible Example
import pandas as pd
pd.DataFrame([dict(a=1, b=[1, 2, 3])]).style.format(na_rep="-").to_html()
# ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()Issue Description
.style.format()'s na_rep is not compatible with non-scalar elements like lists. The problem seems to be that isna(obj) does not return a boolean in this case.
Expected Behavior
format(na_rep="-") should have the intended behaviour of styling using "-" if there is no object in the "b" column, and styling it as usual otherwise.
Note that pd.isna(pd.DataFrame([dict(a=1, b=[1, 2, 3])])) runs without error.
Installed Versions
Details
commit : 4bfe3d07b4858144c219b9346329027024102ab6
python : 3.8.10.final.0
python-bits : 64
OS : Linux
OS-release : 5.13.0-41-generic
Version : #46~20.04.1-Ubuntu SMP Wed Apr 20 13:16:21 UTC 2022
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : sv_SE.UTF-8
LOCALE : sv_SE.UTF-8
pandas : 1.4.2
numpy : 1.22.4
pytz : 2022.1
dateutil : 2.8.2
pip : 20.0.2
setuptools : 44.0.0
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.2
IPython : None
pandas_datareader: None
bs4 : None
bottleneck : None
brotli : None
fastparquet : None
fsspec : None
gcsfs : None
markupsafe : 2.1.1
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : None
snappy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
zstandard : None