R/pipe_helpers.R

In ManifestoProject/manifestoR: Access and Process Data and Documents of the Manifesto Project

#' Prefix a string of text
#' 
#' Convenience function to use with magrittr
#' wraps \code{\link{paste0}}, hence vectorised as \code{\link{paste0}}
#' 
#' @param text goes to the end, rest 
#' @param ... goes to the front. 
prefix <- function(text, ...) {
  paste0(..., text)
}

#' Apply a function if and only if test is TRUE
#' 
#' otherwise return input value unchanged
#' 
#' iffn is ... if and only if test is FALSE
#' 
#' @param obj object to apply test and fun to
#' @param test logical or function to apply to test
#' @param fun function to apply
#' @param ... passed on to test
iff <- function(obj, test, fun, ...) {
  if ( (is.function(test) && test(obj)) || 
       (is.logical(test) && test) ) {
    fun(obj, ...) 
  } else {
    obj
  }
}

#' @rdname iff
iffn <- function(obj, test, fun, ...) {
  if ( (is.function(test) && !test(obj)) || 
       (is.logical(test) && !test) ) {
    fun(obj, ...) 
  } else {
    obj
  }
}


#' Replace NAs in vector with fixed value
#' 
#' @rdname na_action
#' @param vec vector to replace NAs in
#' @param value value to inject for NA
na_replace <- function(vec, value = 0L) {
  vec[is.na(vec)] <- value
  return(vec)
}