New feature: update data dictionary for multiple choice checkbox variables.

[RoryChenXY]

A function I wrote for my own project and thought this could be useful:

expand_checkbox_dictionary <- function(dict,
                                       var_col = "field_name",
                                       type_col = "field_type",
                                       label_col = "field_label",
                                       choice_col = "select_choices_or_calculations") {
  
  dict_updated <- dict |>
    dplyr::mutate(.row_id = dplyr::row_number()) |>
    dplyr::group_split(.row_id, .keep = TRUE) |>
    purrr::map_dfr(function(row) {
      
      if (row[[type_col]] != "checkbox") {
        return(dplyr::select(row, -.row_id))
      }
      
      choices <- REDCapR::checkbox_choices(row[[choice_col]])
      
      if (nrow(choices) == 0) {
        return(dplyr::select(row, -.row_id))
      }
      
      out <- row[rep(1, nrow(choices)), ] |>
        dplyr::bind_cols(choices) |>
        dplyr::mutate(
          !!var_col := paste0(.data[[var_col]], "___", id)
        )
      
      if (!is.null(label_col) && label_col %in% names(out)) {
        out <- out |>
          dplyr::mutate(
            !!label_col := paste0(.data[[label_col]], "_", label),
            !!type_col := "yesno"
          )
      }
      
      out |>
        dplyr::select(-.row_id) |>
        dplyr::select(-id, -label)
      
    })
}

[RoryChenXY]

copilot helped with the documentation:

#' Expand checkbox variables in a REDCap data dictionary into yes/no fields
#'
#' REDCap checkbox fields are stored in the data dictionary as a single row with
#' coded choices (e.g., `"1, Choice A | 2, Choice B"`). In exported data, each
#' choice becomes its own variable named like `field_name___1`, `field_name___2`,
#' etc. This helper expands dictionary rows where `field_type == "checkbox"` into
#' one row per choice, updating the variable name column accordingly.
#'
#' For checkbox rows with parsable choices, the function:
#' \itemize{
#'   \item Replicates the original row once per choice.
#'   \item Appends `___<id>` to the variable name (using the choice id from
#'     \code{\link[REDCapR]{checkbox_choices}}).
#'   \item Optionally appends \code{_<label>} to \code{label_col} and sets
#'     \code{type_col} to `"yesno"`.
#' }
#'
#' Non-checkbox rows (or checkbox rows with zero parsed choices) are returned
#' unchanged.
#'
#' @param dict A data frame (typically a REDCap data dictionary) containing at
#'   least the columns referenced by \code{var_col}, \code{type_col}, and
#'   \code{choice_col}.
#' @param var_col Character(1). Name of the column in \code{dict} containing the
#'   REDCap variable/field name (default `"field_name"`).
#' @param type_col Character(1). Name of the column in \code{dict} containing the
#'   field type (default `"field_type"`). Rows with value `"checkbox"` will be
#'   expanded.
#' @param label_col Character(1). Name of the column in \code{dict} containing the
#'   field label (default `"field_label"`). If this column exists in the input,
#'   expanded rows will have \code{"_<choice label>"} appended and the field type
#'   set to `"yesno"`.
#' @param choice_col Character(1). Name of the column in \code{dict} containing
#'   checkbox choices (default `"select_choices_or_calculations"`), passed to
#'   \code{\link[REDCapR]{checkbox_choices}}.
#'
#' @return A data frame like \code{dict}, but with checkbox rows expanded into
#'   multiple rows (one per choice). The output preserves the original columns
#'   (except internal helper columns), and returns rows in the original order
#'   with checkbox rows replaced by their expanded equivalents.
#'
#' @details
#' This function relies on \code{\link[REDCapR]{checkbox_choices}} to parse the
#' \code{choice_col} text into choice ids and labels. If parsing yields zero
#' choices, the checkbox row is left unchanged.
#'
#' @examples
#' \dontrun{
#' # dict <- REDCapR::redcap_metadata_read(...)$data
#' dict2 <- expand_checkbox_dictionary(dict)
#'
#' # Use different column names if your dictionary is non-standard:
#' dict2 <- expand_checkbox_dictionary(
#'   dict,
#'   var_col = "name",
#'   type_col = "type",
#'   label_col = "label",
#'   choice_col = "choices"
#' )
#' }
#'
#' @export
expand_checkbox_dictionary <- function(dict,
                                      var_col = "field_name",
                                      type_col = "field_type",
                                      label_col = "field_label",
                                      choice_col = "select_choices_or_calculations") {
  # ...
}