R/write.R

In eguidotti/eap: Guidotti Miscellaneous

#' Safe CSV writer
#' 
#' Sorts by key and checks duplicates. Does not overwrite existing file.
#' 
#' @param x the data to write. It gets internally coerced to \code{data.table} preserving col names but not row names.
#' @param file the output file name.
#' @param key one or more column names to check duplicates.
#' @param na the string to use for missing values in the data. 
#' @param create if \code{TRUE}, creates the directory if it does not exist.
#' @param ... additional arguments passed to \code{\link[data.table]{fwrite}}.
#' 
#' @return The file name.
#' 
#' @export
#' 
swrite <- function(x, file, key = NULL, na = "", create = FALSE, ...){
  
  x <- data.table(x, key = key)
  
  if(!is.null(key)) if(any(duplicated(x, by = key)))
    stop(sprintf("Duplicated rows for %s", paste(key, collapse = ", ")))
  
  if(file.exists(file)) 
    stop(sprintf("File already exists: %s", file))
  
  if(create){
    dir <- dirname(file)
    if(!dir.exists(dir))
      dir.create(dir, recursive = TRUE)
  }
  
  fwrite(x, file = file, na = na, ...)
  
}