R/compare_by_group.R

In clinCompare: Dataset Comparison with 'CDISC' Validation for Clinical Trial Data

#' Compare Two Datasets by Group
#'
#' @description
#' Compares two datasets within subgroups defined by grouping variables.
#' Performs separate comparisons for each group and returns results organized
#' by group.
#'
#' @param df1 A data frame representing the first dataset.
#' @param df2 A data frame representing the second dataset.
#' @param group_vars A character vector of column names to group by.
#' @return A list of comparison results for each group.
#' @export
#' @examples
#' \donttest{
#'   df1 <- data.frame(region = c("A", "A", "B"), value = c(10, 20, 30),
#'                     stringsAsFactors = FALSE)
#'   df2 <- data.frame(region = c("A", "A", "B"), value = c(10, 25, 30),
#'                     stringsAsFactors = FALSE)
#'   compare_by_group(df1, df2, group_vars = "region")
#' }

compare_by_group <- function(df1, df2, group_vars) {
  if (!all(group_vars %in% names(df1)) || !all(group_vars %in% names(df2))) {
    stop("Grouping variables must be present in both datasets.")
  }

  # Splitting datasets by groups
  df1_split <- split(df1, df1[, group_vars, drop = FALSE])
  df2_split <- split(df2, df2[, group_vars, drop = FALSE])

  # Identifying unique groups in both datasets
  all_groups <- union(names(df1_split), names(df2_split))

  # Comparing each group
  results <- lapply(all_groups, function(group) {
    group_df1 <- df1_split[[group]]
    group_df2 <- df2_split[[group]]
    if (!is.null(group_df1) && !is.null(group_df2)) {
      compare_datasets(group_df1, group_df2)
    } else {
      NULL
    }
  })

  names(results) <- all_groups
  return(results)
}