lf-shaw opened a new issue #8446:
URL: https://github.com/apache/arrow/issues/8446
I wanna filter dataset on some (pandas) category field, but python crashed.
Some sample code as follows
```python
import pandas as pd
import pyarrow as pa
import pyarrow.parquet as pq
import pyarrow.dataset as ds
# B is category
df = pd.DataFrame({'A': range(4), 'B': list('bccd')})
df['B'] = df['B'].astype('category')
# save to parquet file
table = pa.Table.from_pandas(df)
pq.write_table(table, 'test.parquet')
# read with dataset
dataset = ds.dataset('test.parquet')
# it's ok
dataset.to_table().to_pandas()
# it's ok
dataset.to_table(filter=ds.field('A') > 2).to_pandas()
# it crashed
dataset.to_table(filter=ds.field('B') == 'b').to_pandas()
```
the crash message
```sh
ValueOrDie called on an error: Type error: Cannot compare scalars of
differing type: dictionary<values=string, indices=int32, ordered=0> vs string
```
I know in C++ `arrow::DictionaryArray` of course cannot comapre with string.
But I wanna know is there any possible to filter on category field in python?
Thanks for your attention, and Thanks for this brilliant lib.
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