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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2021/05/03 21:56:57 UTC

[GitHub] [arrow] sa- opened a new issue #10235: C Data Interface: which one is the offsets buffer?

sa- opened a new issue #10235:
URL: https://github.com/apache/arrow/issues/10235


   Hey,
   
   I'm trying to implement the C Data Interface in Julia. A column of Strings looks like this in memory:
   <img width="388" alt="image" src="https://user-images.githubusercontent.com/1297369/116938172-9dddc600-ac6a-11eb-964d-8cb8ba4aa4dd.png">
   
   There are 3 buffers. Correct me if I'm wrong but the first buffer is always the validity bitmap.
   How do I know which one is the offsets buffer and which one is the data buffer?
   
   https://arrow.apache.org/docs/format/CDataInterface.html#c.ArrowArray.buffers this link doesn't specify which one comes first. And the [columnar format spec](https://arrow.apache.org/docs/format/Columnar.html#variable-size-binary-layout) only says that there is an offsets and a data buffer, but doesn't necessarily say offsets is the 2nd buffer and data is the 3rd


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[GitHub] [arrow] jorisvandenbossche closed issue #10235: C Data Interface: which one is the offsets buffer?

Posted by GitBox <gi...@apache.org>.

jorisvandenbossche closed issue #10235:
URL: https://github.com/apache/arrow/issues/10235


   


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[GitHub] [arrow] jorisvandenbossche commented on issue #10235: C Data Interface: which one is the offsets buffer?

Posted by GitBox <gi...@apache.org>.

jorisvandenbossche commented on issue #10235:
URL: https://github.com/apache/arrow/issues/10235#issuecomment-831896143


   See this table: https://arrow.apache.org/docs/format/Columnar.html#buffer-listing-for-each-layout So for variable sized binary (or string), the 2nd buffer are offsets and 3rd buffer is the data


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[GitHub] [arrow] sa- commented on issue #10235: C Data Interface: which one is the offsets buffer?

Posted by GitBox <gi...@apache.org>.

sa- commented on issue #10235:
URL: https://github.com/apache/arrow/issues/10235#issuecomment-832498734


   Thank you very much!


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