Extracting distinct periods given stock split dates.

get_split_date_periods.R

get_split_date_periods <- function(split_dates) {
  n_splits <- length(split_dates)
  if (n_splits > 1) {
    split_date_periods <- list()
    iterable <- c(1, 1:n_splits)
    for (i in 1:length(iterable)) {
      if (i == 1) {
        split_date_periods[[i]] <- sprintf("/%s", split_dates[iterable[i]] - 1)
      } else if (i == length(iterable)) {
        split_date_periods[[i]] <- sprintf("%s/", split_dates[iterable[i]])
      } else {
        split_date_periods[[i]] <- sprintf("%s/%s", split_dates[iterable[i]], split_dates[iterable[i + 1]] - 1)
      }
    }
    return(split_date_periods)
  } else if (n_splits == 1) {
    split_date_periods <- list()
    split_date_periods[[1]] <- sprintf("/%s", split_dates - 1)
    split_date_periods[[2]] <- sprintf("%s/", split_dates)
    return(split_date_periods)
  } else {
    message("No split date periods.")
  }
}