[C++, Python] Allow specifying column names to CSV reader

[asfimport]

Currently I think there is no way to specify custom column names for CSV files. It's possible to specify the full schema of the file, but not just column names.

See the related discussion here: ARROW-3722

The goal of this is to re-use the CSV type-inference but still allow people to specify custom names for the columns. As far as I know, there is currently no way to set column names post-hoc, so we should provide a way to specify them before reading the file.

Related to this, ParseOptions(header_rows=0) is not currently implemented.

Is there any current way to do this or does this need to be implmented?

Reporter: Philipp Moritz / @pcmoritz
Assignee: Ben Kietzman / @bkietz

PRs and other links:

• GitHub Pull Request #4557

_{Note: This issue was originally created as ARROW-4912. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
If there's no way to change column names post-hoc, then perhaps we should just add one? That sounds more universal than adding ad hoc options to the CSV reader.

As for the header_rows=0, can you open a separate issue?

[asfimport]

Francois Saint-Jacques / @fsaintjacques:
Issue resolved by pull request 4557
#4557