[GitHub] [arrow] AlenkaF commented on issue #36308: [Python] Conversion of numpy array of bytes (dtype='S') ignores length

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

AlenkaF commented on issue #36308:
URL: https://github.com/apache/arrow/issues/36308#issuecomment-1608760885

   The logic of conversion to strings in an array constructor does look faulty to me. In the case you mention the bytes get handled correctly if using the default conversion data type which is `binary`:
   
   ```python
   >>> c = pa.array(a)
   >>> c
   <pyarrow.lib.BinaryArray object at 0x115dd6440>
   [
     61,
     6162,
     616263
   ]
   >>> c.to_numpy(zero_copy_only=False)
   array([b'a', b'ab', b'abc'], dtype=object)
   ```
   
   if we cast the `BinaryArray` to the string dtype and call `to_numpy()` we get the expected result (with an object dtype):
   
   ```python
   >>> c.cast(pa.string())
   <pyarrow.lib.StringArray object at 0x115dd6500>
   [
     "a",
     "ab",
     "abc"
   ]
   >>> c.cast(pa.string()).to_numpy(zero_copy_only=False)
   array(['a', 'ab', 'abc'], dtype=object)
   ```
   
   But I suggest we wait for an extra opinion before you start working on a PR.


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