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https://issues.apache.org/jira/browse/ARROW-11882?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17332231#comment-17332231
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Andrew Lamb commented on ARROW-11882:
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Migrated to github: https://github.com/apache/arrow-rs/issues/199
> [Rust] Implement Debug printing "kernel"
> ----------------------------------------
>
> Key: ARROW-11882
> URL: https://issues.apache.org/jira/browse/ARROW-11882
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Rust
> Reporter: Andrew Lamb
> Priority: Major
>
> [~jorgecarleitao] offered a great way to improve the Debug/Display
> implementations for various Array implementations on
> https://github.com/apache/arrow/pull/9624#issuecomment-790976766
> The only reason we are implementing to_isize/to_usize on NativeType is
> because we have a function to represent an array (for Display) that accepts a
> generic physical type T, and then tries to convert it to a isize depending on
> a logical type (DataType::Date). However, there is already a Many to one
> relationship between logical and physical types.
> Thus, a solution for this is to have the `Debug` function branch off
> depending on the (logical) datatype, implementing the custom string
> representation depending on it, instead of having a loop of native type T and
> then branching off according to the DataType inside the loop.
> I.e. instead of
> {code}
> for i in ... {
> match data_type {
> DataType::Date32 => represent array[i] as date
> DataType::Int32 => represent array[i] as int
> }
> }
> {code}
> imo we should have
> {code}
> match data_type {
> DataType::Date32 => for i in ... {represent array[i] as date}
> DataType::Int32 => for i in ... {represent array[i] as int}
> }
> {code}
> i.e. treat the Display as any other "kernel", where behavior is logical, not
> physical, type-dependent.
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