quentin lhoest created ARROW-9787:
-------------------------------------
Summary: pa.array.to_pandas(types_mapper=...) doesn't change the
dtype
Key: ARROW-9787
URL: https://issues.apache.org/jira/browse/ARROW-9787
Project: Apache Arrow
Issue Type: Bug
Components: Python
Affects Versions: 1.0.0
Reporter: quentin lhoest
Hello !
It looks like it is possible to map arrow types to pandas types using the
`types_mapper` argument in `to_pandas`. However it seems to work only for
`pa.Table.to_pandas` and not `pa.array.to_pandas`.
Example to reproduce:
```
import pyarrow as pa
import pandas as pd
def types_mapper(dtype):
print("Looking at dtype")
if dtype == pa.int64():
print("Changing dtype")
return pd.Int32Dtype()
arr = pa.array([1,2,3], pa.int64())
print(pa.Table.from_arrays([arr],
names=["col"]).to_pandas(types_mapper=types_mapper).col.dtype)
# Prints:
# Looking at dtype
# Changing dtype
# Int32
print(arr.to_pandas(types_mapper=types_mapper).dtype)
# Prints:
# int64
```
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