R/utils-stringr.R

In mtfairbanks/gdt: Tidy Interface to 'data.table'

# stringr utils - These functions are for internal use only

str_c <- function(..., sep = "", collapse = NULL) {
  paste(..., sep = sep, collapse = collapse)
}

str_flatten <- function(string, collapse = "") {
  str_c(string, collapse = collapse)
}

str_detect <- function(string, pattern, fixed = FALSE, perl = FALSE) {
  grepl(pattern, string, fixed = fixed, perl = perl)
}

str_extract <- function(x, pattern, fixed = FALSE, perl = FALSE) {
  regmatches(x, regexpr(pattern, x, fixed = fixed, perl = perl))
}

str_extract_all <- function(x, pattern, fixed = FALSE, perl = FALSE) {
  regmatches(x, gregexpr(pattern, x, fixed = fixed, perl = perl))
}

str_replace <- function(string, pattern, replacement, fixed = FALSE, perl = FALSE) {
  sub(pattern, replacement, string, fixed = fixed, perl = perl)
}

str_replace_all <- function(string, pattern, replacement, fixed = FALSE, perl = FALSE) {
  if (missing(replacement)) {
    replacement <- unname(pattern)
    pattern <- names(pattern)
  } else if (length(pattern) != length(replacement)) {
    if (length(pattern) > 1 & length(replacement) > 1) {
      stop("replacement has to have the same length as pattern")
    } else {
      if (length(replacement) == 1) {
        replacement <- rep(replacement, length(pattern))
      } else {
        pattern <- rep(pattern, length(replacement))
      }
    }
  }

  for (i in 1:length(pattern)) {
    string <- gsub(pattern[[i]], replacement[[i]], string,  perl = perl, fixed = fixed)
  }

  string
}