[jira] [Commented] (ARROW-1990) [JS] Add "DataFrame" object

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-1990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16327337#comment-16327337 ] 

ASF GitHub Bot commented on ARROW-1990:
---------------------------------------

TheNeuralBit opened a new pull request #1482: ARROW-1990: [JS] Add "DataFrame" object
URL: https://github.com/apache/arrow/pull/1482
 
 
   This PR moves the `Table` class out of the Vector hierarchy and adds optimized dataframe operations to it. Currently implements an optimized `scan()` method, `filter(predicate)`, `count()`, and `countBy(column_name)` (only works on dictionary-encoded columns).
   
   Some usage examples, based on the file generated by `js/data/test/tables/generate.py`:
   ``` js
   > let table = Table.from(...);
   > let table = Table.from([fs.readFileSync('./test/data/tables/generated.arrow')])
   undefined
   > table.count()
   1000000
   > table.filter(col('lat').gteq(0)).count()
   499718
   > table.countBy('origin').asJSON()
   { Charlottesville: 166839,
     'New York': 166251,
     'San Francisco': 166642,
     Seattle: 166659,
     'Terre Haute': 166756,
     'Washington, DC': 166853 }
   > table.filter(col('lng').gteq(0)).countBy('origin').asJSON()
   { Charlottesville: 83109,
     'New York': 83221,
     'San Francisco': 83515,
     Seattle: 83362,
     'Terre Haute': 83314,
     'Washington, DC': 83479 }
   ```

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> [JS] Add "DataFrame" object
> ---------------------------
>
>                 Key: ARROW-1990
>                 URL: https://issues.apache.org/jira/browse/ARROW-1990
>             Project: Apache Arrow
>          Issue Type: New Feature
>          Components: JavaScript
>            Reporter: Brian Hulette
>            Assignee: Brian Hulette
>            Priority: Major
>              Labels: pull-request-available
>
> Add a TypeScript class that can perform optimized dataframe operations on an arrow {{Table}} and/or {{StructVector}}. Initially this should include operations like filtering, counting, and scanning. Eventually this class could include more operations like sorting, count by/group by, etc...



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