Description
Pandas version checks
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I have checked that this issue has not already been reported.
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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
import pyarrow as pa
arr = ["foo", "bar"]
table = pa.table(
{"arr": pa.array(arr, 'large_string')}
)
exchange_df = table.__dataframe__()
from pandas.core.interchange.from_dataframe import from_dataframe
from_dataframe(exchange_df)Issue Description
I get
Traceback (most recent call last):
File "t.py", line 30, in <module>
from_dataframe(exchange_df)
File "/home/marcogorelli/pandas-dev/pandas/core/interchange/from_dataframe.py", line 52, in from_dataframe
return _from_dataframe(df.__dataframe__(allow_copy=allow_copy))
File "/home/marcogorelli/pandas-dev/pandas/core/interchange/from_dataframe.py", line 73, in _from_dataframe
pandas_df = protocol_df_chunk_to_pandas(chunk)
File "/home/marcogorelli/pandas-dev/pandas/core/interchange/from_dataframe.py", line 125, in protocol_df_chunk_to_pandas
columns[name], buf = string_column_to_ndarray(col)
File "/home/marcogorelli/pandas-dev/pandas/core/interchange/from_dataframe.py", line 242, in string_column_to_ndarray
assert protocol_data_dtype[1] == 8 # bitwidth == 8
AssertionErrorExpected Behavior
Raise informative error message, in particular not using assert
cc @AlenkaF @jorisvandenbossche
Installed Versions
INSTALLED VERSIONS
commit : 7059b7b
python : 3.8.16.final.0
python-bits : 64
OS : Linux
OS-release : 5.10.102.1-microsoft-standard-WSL2
Version : #1 SMP Wed Mar 2 00:30:59 UTC 2022
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : en_GB.UTF-8
LOCALE : en_GB.UTF-8
pandas : 2.1.0.dev0+573.g7059b7b864.dirty
numpy : 1.23.5
pytz : 2023.3
dateutil : 2.8.2
setuptools : 67.6.1
pip : 23.1
Cython : 0.29.33
pytest : 7.3.1
hypothesis : 6.72.0
sphinx : 6.1.3
blosc : 1.11.1
feather : None
xlsxwriter : 3.1.0
lxml.etree : 4.9.2
html5lib : 1.1
pymysql : 1.0.3
psycopg2 : 2.9.6
jinja2 : 3.1.2
IPython : 8.12.0
pandas_datareader: None
bs4 : 4.12.2
bottleneck : 1.3.7
brotli :
fastparquet : 2023.2.0
fsspec : 2023.4.0
gcsfs : 2023.4.0
matplotlib : 3.6.3
numba : 0.56.4
numexpr : 2.8.4
odfpy : None
openpyxl : 3.1.0
pandas_gbq : None
pyarrow : 11.0.0
pyreadstat : 1.2.1
pyxlsb : 1.0.10
s3fs : 2023.4.0
scipy : 1.10.1
snappy :
sqlalchemy : 2.0.9
tables : 3.8.0
tabulate : 0.9.0
xarray : 2023.1.0
xlrd : 2.0.1
zstandard : 0.21.0
tzdata : 2023.3
qtpy : None
pyqt5 : None
None