R/chamber.split.R

In rambur: Design and Analysis of Intertidal Chamber Experiments

#' Chamber: Splitting Profile
#'
#' A function to split the "Profile.txt" with more than 1000 lines into smaller files.
#'
#' @param file.path a character string, path to the original "Profile.txt" file.
#' @param max.lines an integer, number of lines in new files.
#' @param overlap.lines an integer, number of lines shared between two consecutive files.
#' @param folder.path a character string, path to the new files after splitting.
#'
#' @return No return value, called for side effects. The function splits
#'   "Profile.txt" and saves each part into its own subdirectory.
#'
#' @export
chamber.split <- function(file.path,
                          max.lines = 960,
                          overlap.lines = 120,
                          folder.path = NULL){

  if (is.null(folder.path)) {
    folder.path <- dirname(file.path)
  }

  profile <- readLines(file.path)
  total.lines <- length(profile)

  start.lines <- seq(from = 1, to = total.lines, by = max.lines - overlap.lines)
  end.lines <- start.lines + max.lines - 1
  end.lines[end.lines > total.lines] <- total.lines

  message("splitting '", basename(file.path), "' with ", total.lines, " lines into:")

  for (i in 1:length(start.lines)){

    start.line <- start.lines[i]
    end.line <- end.lines[i]

    sub.profile <- profile[start.line:end.line]

    start.time <- head(sub.profile, 1) %>% substr(1, 10) %>% as.numeric %>% as.POSIXct(tz = "UTC") %>% format("%Y%m%d_%H%M")
    end.time <- tail(sub.profile, 1) %>% substr(1, 10) %>% as.numeric %>% as.POSIXct(tz = "UTC") %>% format("%Y%m%d_%H%M")

    # sub.folder.path <- file.path(folder.path, sprintf("part-%02d", i))
    sub.folder.path <- file.path(folder.path, paste0(start.time, "_to_", end.time)) #more informative sub folder names

    if (!dir.exists(sub.folder.path)) {
      dir.create(sub.folder.path, recursive = TRUE)
    }

    write.table(sub.profile, file.path(sub.folder.path, "Profile.txt"),
                quote = FALSE,
                row.names = FALSE,
                col.names = FALSE)

    message(sprintf("%s/Profile.txt (lines %d - %d)",
                    sub.folder.path, start.line, end.line))

  }


}