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https://issues.apache.org/jira/browse/ARROW-15260?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17516837#comment-17516837
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Neal Richardson commented on ARROW-15260:
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> although C++ gives us errors if we try to insert a field reference to
> {{__filename}} in an {{Expression}}
This is tricky because we (and apparently elsewhere in the C++ code) have logic
to filter out secret internal columns like this:
https://github.com/apache/arrow/blob/master/r/R/query-engine.R#L159-L163.
Sounds like we need to find a safe way to loosen that, or otherwise rethink the
implementation.
In terms of UX in R, a special helper like {{add_filenames <- function()
Expression$field_ref("__filename")}} that you could call like {{mutate(ds,
file_col = add_filenames())}} might be a reasonable interface to this.
> [R] open_dataset - add file_name as column
> ------------------------------------------
>
> Key: ARROW-15260
> URL: https://issues.apache.org/jira/browse/ARROW-15260
> Project: Apache Arrow
> Issue Type: New Feature
> Components: R
> Reporter: Martin du Toit
> Priority: Minor
>
> Hi. Is it possible to add the file_name as a column to a dataset?
> {code:r}
> ds <- open_dataset(.....)
> list_of_files <- ds$files
> {code}
> This works, but I need the file_name as a column.
> Thanks
>
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