R/path_string.R

In tidypmc: Parse Full Text XML Documents from PubMed Central

#' Print a hierarchical path string
#'
#' Print a hierarchical path string from a vector of names and levels
#'
#' @param x a vector of names
#' @param n a vector of numbers with indentation level
#'
#' @return a character vector
#'
#' @note Used by \code{\link{pmc_text}} to print full path to subsection title
#'
#' @author Chris Stubben
#'
#' @examples
#' x <- c("carnivores", "bears", "polar", "grizzly", "cats", "tiger", "rodents")
#' n <- c(1, 2, 3, 3, 2, 3, 1)
#' path_string(x, n)
#' @export

path_string <- function(x, n) {
  n2 <- length(n)
  if (is.factor(x)) x <- as.character(x)
  if (!is.numeric(n)) stop("n should be a vector of numbers")
  if (n2 != length(x)) stop("x and n should be the same length")
  z <- vector("list", n2)
  if (min(n) > 1) n <- n - min(n) + 1
  ## start with empty vector
  path <- ""
  for (i in seq_len(n2)) {
    ## add name at position n[i]
    path[n[i]] <- x[i]
    ## drop names if n[i] decreases
    path <- path[seq_len(n[i])]
    ### paste together names
    z[[i]] <- paste(path, collapse = "; ")
  }
  z <- unlist(z)
  ## check if any NA?
  z <- gsub("NA; ", "", z)
  z
}