R/tier_to_df.R

In phonfieldwork: Linguistic Phonetic Fieldwork Tools

#' TextGrid's tier to dataframe
#'
#' Convert selected tier from a Praat TextGrid to a dataframe.
#'
#' @author George Moroz <agricolamz@gmail.com>
#'
#' @param file_name string with a filename or path to the TextGrid
#' @param tier value that could be either ordinal number of the tier either
#' name of the tier. By default is '1'.
#'
#' @return a dataframe with columns:  \code{id}, \code{time_start},
#' \code{time_end}, \code{content}, , \code{tier_name}
#'
#' @examples
#' tier_to_df(system.file("extdata", "test.TextGrid",
#'   package = "phonfieldwork"
#' ))
#' tier_to_df(
#'   system.file("extdata", "test.TextGrid",
#'     package = "phonfieldwork"
#'   ),
#'   "intervals"
#' )
#' @export
#'

tier_to_df <- function(file_name, tier = 1) {
  df <- textgrid_to_df(file_name = file_name)

  if (is.numeric(tier)) {
    if (tier > max(df$tier)) {
      stop(paste0("It looks like there is no tier number '", tier, "'"))
    }
    results <- df[df$tier == tier, ]
  } else if (is.character(tier)) {
    if (!(tier %in% unique(df$tier_name))) {
      stop(paste0("It looks like there is no any tier with a name '", tier, "'"))
    }
    results <- df[df$tier_name == tier, ]
  }
  return(results)
}