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https://issues.apache.org/jira/browse/ARROW-15479?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Antoine Pitrou updated ARROW-15479:
-----------------------------------
    Labels: good-second-issue kernel  (was: kernel)

> [C++] Cast fixed size list to compatible fixed size list type (other values 
> type, other field name)
> ---------------------------------------------------------------------------------------------------
>
>                 Key: ARROW-15479
>                 URL: https://issues.apache.org/jira/browse/ARROW-15479
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: C++
>            Reporter: Joris Van den Bossche
>            Priority: Major
>              Labels: good-second-issue, kernel
>
> Casting a FixedSizeListArray to a compatible type but only a different field 
> name isn't implemented:
> {code:python}
> >>> my_type = pa.list_(pa.field("element", pa.int64()), 2)
> >>> arr = pa.FixedSizeListArray.from_arrays(pa.array([1, 2, 3, 4, 5, 6]), 2)
> >>> arr.type
> FixedSizeListType(fixed_size_list<item: int64>[2])
> >>> my_type
> FixedSizeListType(fixed_size_list<element: int64>[2])
> >>> arr.cast(my_type)
> ...
> ArrowNotImplementedError: Unsupported cast from fixed_size_list<item: 
> int64>[2] to fixed_size_list using function cast_fixed_size_list
> {code}
> While the similar operation with a variable sized list actually works:
> {code:python}
> >>> my_type = pa.list_(pa.field("element", pa.int64()))
> >>> arr = pa.array([[1, 2], [3, 4]], pa.list_(pa.int64()))
> >>> arr.type
> ListType(list<item: int64>)
> >>> arr.cast(my_type).type
> ListType(list<element: int64>)
> {code}



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