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https://issues.apache.org/jira/browse/ARROW-2205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16377068#comment-16377068
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ASF GitHub Bot commented on ARROW-2205:
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cpcloud commented on a change in pull request #1650: ARROW-2205: [Python]
Option for integer object nulls
URL: https://github.com/apache/arrow/pull/1650#discussion_r170637799
##########
File path: python/pyarrow/tests/test_convert_pandas.py
##########
@@ -615,6 +615,36 @@ def test_int_object_nulls(self):
_check_pandas_roundtrip(df, expected=expected,
expected_schema=schema)
+ def test_int_object_nulls_option(self):
Review comment:
It doesn't look like you're using `self` here. Can you make this into a test
function and
[`pytest.mark.parametrize`](https://docs.pytest.org/en/latest/parametrize.html)
it on the `int_dtypes` parameter?
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> [Python] Option for integer object nulls
> ----------------------------------------
>
> Key: ARROW-2205
> URL: https://issues.apache.org/jira/browse/ARROW-2205
> Project: Apache Arrow
> Issue Type: New Feature
> Components: C++, Python
> Affects Versions: 0.8.0
> Reporter: Albert Shieh
> Priority: Major
> Labels: pull-request-available
>
> I have a use case where the loss of precision in casting integers to floats
> matters, and pandas supports storing integers with nulls without loss of
> precision in object columns. However, a roundtrip through arrow will cast the
> object columns to float columns, even though the object columns are stored in
> arrow as integers with nulls.
> This is a minimal example demonstrating the behavior of a roundtrip:
> {code}
> import numpy as np
> import pandas as pd
> import pyarrow as pa
> df = pd.DataFrame({"a": np.array([None, 1], dtype=object)})
> df_pa = pa.Table.from_pandas(df).to_pandas()
> print(df)
> print(df_pa)
> {code}
> The output is:
> {code}
> a
> 0 None
> 1 1
> a
> 0 NaN
> 1 1.0
> {code}
> This seems to be the desired behavior, given test_int_object_nulls in
> test_convert_pandas.
> I think it would be useful to add an option in the to_pandas methods to allow
> integers with nulls to be returned as object columns. The option can default
> to false in order to preserve the current behavior.
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