[ARROW-8209] [Python] Accessing duplicate column of Table by name gives wrong error

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.17.0
• Component/s: Python
• Labels: beginner pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/24406
• Assignee: Wes McKinney
• Reporter: Joris Van den Bossche
• Created: 25/Mar/20 14:58
• Updated: 11/Jan/23 07:58
• Resolved: 04/Apr/20 22:55

Description

When you have a table with duplicate column names and you try to access this column, you get an error about the column not existing:

>>> table = pa.table([pa.array([1, 2, 3]), pa.array([4, 5, 6]), pa.array([7, 8, 9])], names=['a', 'b', 'a']) 

>>> table.column('a')                                                                                                                                                                                          
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-6-14fad86d3142> in <module>
----> 1 table.column('a')

~/scipy/repos/arrow/python/pyarrow/table.pxi in pyarrow.lib.Table.column()

KeyError: 'Column a does not exist in table'

It should rather give an error message about the column name being duplicate.

Issue Links

• links to: GitHub Pull Request #6831