Re: [I] [Python][Parquet] When reading, int32 (Date) is treated as object [arrow]

["jorisvandenbossche (via GitHub)" <gi...@apache.org>]

jorisvandenbossche commented on issue #47464:
URL: https://github.com/apache/arrow/issues/47464#issuecomment-3257645492

   Similarly as in https://github.com/apache/arrow/issues/47460, the issue is the conversion from Arrow->pandas, and not in reading the parquet file.
   
   Parquet has a date type, and Arrow as well. And so when reading the Parquet file into an Arrow table using pyarrow, you would see that the type is preserved. You can try:
   
   ```python
   import pyarrow.parquet as pq
   table = pq.read_table("C:/Users/qnsv2207/Desktop/test_amphi_compare.parquet")
   table
   ```
   
   This should show that the "OrderDate" column has a `date32` type.
   
   But then pandas does not have a built-in "date" type. Therefore, in the arrow->pandas conversion, pyarrow by default converts its date types into an `object` column with python datetime.date objects. 
   
   See the documentation about this at https://arrow.apache.org/docs/python/pandas.html#date-types, which also mentions the `date_as_object=False` option you can specify in `to_pandas()` to avoid this conversion to object dtype.
   


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