[ARROW-18049] [R] Support column renaming in col_select argument to file reading functions

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: R
• Labels: good-first-issue
• External issue URL: https://github.com/apache/arrow/issues/33251
• Assignee: Unassigned
• Reporter: Nicola Crane
• Created: 14/Oct/22 11:38
• Updated: 11/Jan/23 11:57

Description

We should support the ability to rename columns when reading in data via the CSV/Parquet/Feather/JSON file readers.

We currently have an argument col_select, which allows users to choose which columns to read in, but renaming doesn't work.

To implement this, we'd need to check if any columns have been renamed by col_select and then updating the schema of the object being returned once the file has been read.

library(readr)
library(arrow)
readr::read_csv(readr_example("mtcars.csv"), col_select = c(not_hp = hp))
#> # A tibble: 32 × 1
#>    not_hp
#>     <dbl>
#>  1    110
#>  2    110
#>  3     93
#>  4    110
#>  5    175
#>  6    105
#>  7    245
#>  8     62
#>  9     95
#> 10    123
#> # … with 22 more rows
arrow::read_csv_arrow(readr_example("mtcars.csv"), col_select = c(not_hp = hp))
#> # A tibble: 32 × 1
#>       hp
#>    <int>
#>  1   110
#>  2   110
#>  3    93
#>  4   110
#>  5   175
#>  6   105
#>  7   245
#>  8    62
#>  9    95
#> 10   123
#> # … with 22 more rows