R/merge_files.r

In hcc-donder/commcoll: Collection of functions for use at Haywood Community College (HCC)

#' Merge all files in a specified path
#'
#' This function allows you to merge all the files in a specified folder.
#' It handles removing the extra header lines, if necessary. It also
#' adds the file name as an extra variable, if this is necessary.
#'
#' @param path Defaults to the current working directory using getwd()
#' @param pattern The pattern used to filter the files prior to the merge
#' @param type The type of merge. Possible options are csv, fixed, other
#' @param FNvar The name of the variable which will contain the filename. Will only add filename if this parameter has a variable name.
#' @keywords file
#' @export
#' @importFrom dplyr bind_rows
#'
merge_files <- function( path=getwd(), pattern="*", type="csv", FNvar="",
                        col_types=cols(.default=col_character()), ... ) {
    if (type=="csv") {
        readfile <- readr::read_csv
    } else if (type=="fixed") {
        readfile <- readr::read_fwf
    } else {
        readfile <- readr::read_lines
    }

    readfile_addFileName <- function(.file, ...) {
        dat <- readfile( .file, ... )
        dat[[FNvar]] <- as.character(.file)
        dat    # return the dataframe
    }

    if (FNvar!="") {
        readfun <- readfile_addFileName
    } else {
        readfun <- readfile
    }

    df <- list.files( path        = path,
                      pattern     = pattern,
                      full.names  = TRUE,
                      ignore.case = TRUE ) %>%
          lapply(readfun,col_types=col_types, ...) %>%
          bind_rows
}