[ARROW-6882] [Python] cannot create a chunked_array from dictionary_encoding result

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.15.0
• Fix Version/s: 0.15.1, 0.16.0
• Component/s: Python
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/23210
• Assignee: Joris Van den Bossche
• Reporter: Artem KOZHEVNIKOV
• Created: 14/Oct/19 20:39
• Updated: 11/Jan/23 07:50
• Resolved: 15/Oct/19 02:25

Description

I've experienced a strange error raise when trying to apply `pa.chunked_array` directly on the indices of dictionary_encoding (code is below). Making a memory view solves the problem.

import pyarrow as pa
ca = pa.array(['a', 'a', 'b', 'b', 'c'])                                                                                           
fca = ca.dictionary_encode()                                                                                                       
fca.indices                                                                                                                        
<pyarrow.lib.Int32Array object at 0x1250fb888>
[
  0,
  0,
  1,
  1,
  2
]

pa.chunked_array([fca.indices])                                                                                                    
---------------------------------------------------------------------------
ArrowInvalid                              Traceback (most recent call last)
<ipython-input-44-71ca3b877e1c> in <module>
----> 1 pa.chunked_array([fca.indices])

~/Projects/miniconda3/envs/pyarrow/lib/python3.7/site-packages/pyarrow/table.pxi in pyarrow.lib.chunked_array()

~/Projects/miniconda3/envs/pyarrow/lib/python3.7/site-packages/pyarrow/error.pxi in pyarrow.lib.check_status()

ArrowInvalid: Unexpected dictionary values in array of type int32

# with another memory view it's  OK
pa.chunked_array([fca.indices.view(fca.indices.type)])                 
Out[45]: 
<pyarrow.lib.ChunkedArray object at 0x12508dc78>
[
  [
    0,
    0,
    1,
    1,
    2
  ]
]
 

Issue Links

• links to: GitHub Pull Request #5656