R/extract_datamap.R

In PrenolanM/rsegmenter: What the Package Does (One Line, Title Case)

#' Returns a data.frame containing a mapping between variables, value codes and value labels.
#' @param df data.frame of numeric variables. The file must have been imported using one of haven::read_sav or 
#' rsegmenter::read_data. See the test_datamap example that comes with the package.
#' @export

extract_datamap <- function(df){
  
  # need to add checks to make sure df is the correct
  # input as required
  
  mynames <- colnames(df)
  
  data_map_list <- lapply(mynames,
                          function(x){
                            t(rbind(x,
                                    attr(df[[x]],"label"),
                                    attr(df[[x]],"labels"),
                                    names(attr(df[[x]],"labels"))))
                          }
  )
  
  vars_to_keep <- unlist(lapply(data_map_list,
                                function(x){
                                  dim(x)[2]
                                  }
                                )
                         )
  
  data_map_list <- data_map_list[vars_to_keep==4]
  
  data_map_df <- do.call("rbind.data.frame",
                         data_map_list)
  
  rownames(data_map_df) <- NULL
  colnames(data_map_df) <- c("Variable_Name",
                             "Variable_Label",
                             "Value_Code","Value_Label")
  
  data_map_df[["Value_Code"]] <- as.numeric(as.character(data_map_df[["Value_Code"]]))
  
  data_map_df[["Variable_Order"]] <- seq_along(data_map_df[["Variable_Name"]])
  
  return(data_map_df[c("Variable_Order",
                       "Variable_Name",
                       "Variable_Label",
                       "Value_Code","Value_Label")
                     ]
         )
}