{tidyselect} columns with alphabetical ordering

starts_with_ordered.R

starts_with_ordered <- function(match, decreasing = FALSE) {
  all_vars <- tidyselect::peek_vars()
  matches <- tidyselect::starts_with(match)
  named_matches <- setNames(matches, all_vars[matches])
  named_matches[order(names(named_matches), decreasing = decreasing)]
}

mtcars |>
  dplyr::select(starts_with_ordered("c", decreasing = FALSE)) |> 
  head()
#>                   carb cyl
#> Mazda RX4            4   6
#> Mazda RX4 Wag        4   6
#> Datsun 710           1   4
#> Hornet 4 Drive       1   6
#> Hornet Sportabout    2   8
#> Valiant              1   6

mtcars |>
  dplyr::select(starts_with_ordered("c", decreasing = TRUE)) |> 
  head()
#>                   cyl carb
#> Mazda RX4           6    4
#> Mazda RX4 Wag       6    4
#> Datsun 710          4    1
#> Hornet 4 Drive      6    1
#> Hornet Sportabout   8    2
#> Valiant             6    1

mtcars |>
  dplyr::select(starts_with_ordered("d", decreasing = FALSE)) |> 
  head()
#>                   disp drat
#> Mazda RX4          160 3.90
#> Mazda RX4 Wag      160 3.90
#> Datsun 710         108 3.85
#> Hornet 4 Drive     258 3.08
#> Hornet Sportabout  360 3.15
#> Valiant            225 2.76

mtcars |>
  dplyr::select(starts_with_ordered("d", decreasing = TRUE)) |> 
  head()
#>                   drat disp
#> Mazda RX4         3.90  160
#> Mazda RX4 Wag     3.90  160
#> Datsun 710        3.85  108
#> Hornet 4 Drive    3.08  258
#> Hornet Sportabout 3.15  360
#> Valiant           2.76  225