[jira] [Commented] (ARROW-12657) [C++][Python][Compute] String hex to numeric conversion and bit shifting

["William Malpica (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-12657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17407734#comment-17407734 ] 

William Malpica commented on ARROW-12657:
-----------------------------------------

The ParseHexValue function takes in only two char at time and outputs a uint_8. We could reuse this, but it gets fairly awkward if your string has an odd number of hex digits. I think it would be better to implement something more flexible

> [C++][Python][Compute] String hex to numeric conversion and bit shifting
> ------------------------------------------------------------------------
>
>                 Key: ARROW-12657
>                 URL: https://issues.apache.org/jira/browse/ARROW-12657
>             Project: Apache Arrow
>          Issue Type: New Feature
>          Components: C++, Python
>            Reporter: Franz
>            Assignee: William Malpica
>            Priority: Major
>
> Hi Apache Arrow Community,
> thanks for the great work on this project - it is really a game changer. I've started to use it more frequently since more and more compute kernels became available.
> However, I have a current requirement which I can't fulfill, yet. More concretely, I have hex values as strings. I need to convert them to numeric type (int) and apply bit shifting.
> Currently, I can't find a way to do so. I tried type casts (string to int) like 
> {code:java}
> import pyarrow as pa
> array = pa.array(["0x2001591", "0x2000848", "0x2000123"])
> array.cast(pa.uint32()){code}
> However this results in _ArrowInvalid: Failed to parse string: '0x2000123' as a scalar of type uint32._ 
> Moreover, I will need to apply bit shifting once converted. I'm not sure if there is anything comparable in the compute kernels, yet.
> Thanks for any help in advance.
>  
>  



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