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https://issues.apache.org/jira/browse/ARROW-6578?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Wes McKinney resolved ARROW-6578.
---------------------------------
Resolution: Fixed
Issue resolved by pull request 5556
[https://github.com/apache/arrow/pull/5556]
> [C++] Casting int64 to string columns
> -------------------------------------
>
> Key: ARROW-6578
> URL: https://issues.apache.org/jira/browse/ARROW-6578
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++, Python
> Affects Versions: 0.14.1
> Reporter: Igor Yastrebov
> Assignee: Antoine Pitrou
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.0.0
>
> Time Spent: 2h 10m
> Remaining Estimate: 0h
>
> I wanted to cast a list of a tables to the same schema so I could use
> concat_tables later. However, I encountered ArrowNotImplementedError:
> {code:java}
> ---------------------------------------------------------------------------
> ArrowNotImplementedError Traceback (most recent call last)
> <ipython-input-11-bd4916c221bf> in <module>
> ----> 1 list_tb = [i.cast(mts_schema, safe = True) for i in list_tb]
> <ipython-input-11-bd4916c221bf> in <listcomp>(.0)
> ----> 1 list_tb = [i.cast(mts_schema, safe = True) for i in list_tb]
> ~\AppData\Local\Continuum\miniconda3\envs\cyclone\lib\site-packages\pyarrow\table.pxi
> in itercolumns()
> ~\AppData\Local\Continuum\miniconda3\envs\cyclone\lib\site-packages\pyarrow\table.pxi
> in pyarrow.lib.Column.cast()
> ~\AppData\Local\Continuum\miniconda3\envs\cyclone\lib\site-packages\pyarrow\error.pxi
> in pyarrow.lib.check_status()
> ArrowNotImplementedError: No cast implemented from int64 to string
> {code}
> Some context: I want to read and concatenate a bunch of csv files that come
> from partitioning of the same table. Using cast after reading csv is usually
> significantly faster than specifying column_types in ConvertOptions. There
> are string columns that are mostly populated with integer-like values so a
> particular file can have an integer-only column. This situation is rather
> common so having an option to cast int64 column to string column would be
> helpful.
>
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