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Posted to issues@arrow.apache.org by "Francois Saint-Jacques (Jira)" <ji...@apache.org> on 2019/09/19 14:45:00 UTC
[jira] [Comment Edited] (ARROW-6536) [C++] CSV reader accept schema
[ https://issues.apache.org/jira/browse/ARROW-6536?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16933452#comment-16933452 ]
Francois Saint-Jacques edited comment on ARROW-6536 at 9/19/19 2:44 PM:
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If we don't pass a schema, the minimum we should provide is common options for other readers (Parquet, Json) for selecting columns type hinting when required (JSON, CSV). This way, the dataset facility can write a single function to do this.
I wouldn't tackle extra columns in the reader, only subset + type.
was (Author: fsaintjacques):
If we don't pass a schema, the minimum we should provide is common options for other readers (Parquet, Json) for selecting columns type hinting when required (JSON, CSV).
> [C++] CSV reader accept schema
> ------------------------------
>
> Key: ARROW-6536
> URL: https://issues.apache.org/jira/browse/ARROW-6536
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Neal Richardson
> Priority: Major
> Labels: csv, dataset
>
> The CSV reader lets you specify {{column_types}}, but this is an {{unordered_map}} of column name and type. Why not accept a Schema instead? Isn't that essentially an ordered map? Seems that if you took a Schema, some of the validation of what's being passed in would already have been handled. Plus, I suspect that the Datasets project will want to do even more with passing a Schema (e.g. selecting a subset of columns).
> Thoughts [~pitrou] [~fsaintjacques] [~bkietz]?
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