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