[ARROW-17360] [Python] Order of columns in pyarrow.feather.read_table

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 8.0.1
• Fix Version/s: 11.0.0
• Component/s: Python
• Labels: orc pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/32634
• Assignee: Alenka Frim
• Reporter: NULL
• Created: 09/Aug/22 18:59
• Updated: 11/Jan/23 11:50
• Resolved: 09/Nov/22 10:55

Description

xref https://github.com/pandas-dev/pandas/issues/47944

 

In [1]: df = pd.DataFrame({"a": [1, 2, 3], "b": ["a", "b", "c"]})

# pandas main branch / 1.5
In [2]: df.to_orc("abc")

In [3]: pd.read_orc("abc", columns=['b', 'a'])
Out[3]:
   a  b
0  1  a
1  2  b
2  3  c

In [4]: import pyarrow.orc as orc

In [5]: orc_file = orc.ORCFile("abc")

# reordered to a, b
In [6]: orc_file.read(columns=['b', 'a']).to_pandas()
Out[6]:
   a  b
0  1  a
1  2  b
2  3  c

# reordered to a, b
In [7]: orc_file.read(columns=['b', 'a'])
Out[7]:
pyarrow.Table
a: int64
b: string
----
a: [[1,2,3]]
b: [["a","b","c"]] 

Issue Links

• links to: GitHub Pull Request #14493
• links to: GitHub Pull Request #14528