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https://issues.apache.org/jira/browse/ARROW-2014?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16423719#comment-16423719
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ASF GitHub Bot commented on ARROW-2014:
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xhochy closed pull request #1820: ARROW-2014: [Python] Document read_pandas
method in pyarrow.parquet
URL: https://github.com/apache/arrow/pull/1820
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
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diff --git a/python/doc/source/parquet.rst b/python/doc/source/parquet.rst
index 3d01e1d3c..b68d4d85d 100644
--- a/python/doc/source/parquet.rst
+++ b/python/doc/source/parquet.rst
@@ -68,7 +68,8 @@ Let's look at a simple table:
df = pd.DataFrame({'one': [-1, np.nan, 2.5],
'two': ['foo', 'bar', 'baz'],
- 'three': [True, False, True]})
+ 'three': [True, False, True]},
+ index=list('abc'))
table = pa.Table.from_pandas(df)
We write this to Parquet format with ``write_table``:
@@ -94,6 +95,13 @@ the whole file (due to the columnar layout):
pq.read_table('example.parquet', columns=['one', 'three'])
+When reading a subset of columns from a file that used a Pandas dataframe as
the
+source, we use ``read_pandas`` to maintain any additional index column data:
+
+.. ipython:: python
+
+ pq.read_pandas('example.parquet', columns=['two']).to_pandas()
+
We need not use a string to specify the origin of the file. It can be any of:
* A file path as a string
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> [Python] Document read_pandas method in pyarrow.parquet
> -------------------------------------------------------
>
> Key: ARROW-2014
> URL: https://issues.apache.org/jira/browse/ARROW-2014
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Python
> Reporter: Wes McKinney
> Assignee: Phillip Cloud
> Priority: Major
> Labels: pull-request-available
> Fix For: 0.10.0
>
>
> see discussion in https://github.com/apache/arrow/issues/1302
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