Bioequivalence and Bioavailability Forum • built-in ifelse

built-in ifelse [🇷 for BE/BA]

posted by mittyri – Russia, 2019-04-30 15:05 (2618 d 00:12 ago) – Posting: # 20263
Views: 11,769

Hi ElMaestro,

please see ifelse internals:


function (test, yes, no) 

{

  if (is.atomic(test)) {

    if (typeof(test) != "logical") 

      storage.mode(test) <- "logical"

    if (length(test) == 1 && is.null(attributes(test))) {

      if (is.na(test)) 

        return(NA)

      else if (test) {

        if (length(yes) == 1) {

          yat <- attributes(yes)

          if (is.null(yat) || (is.function(yes) && identical(names(yat), 

            "srcref"))) 

            return(yes)

        }

      }

      else if (length(no) == 1) {

        nat <- attributes(no)

        if (is.null(nat) || (is.function(no) && identical(names(nat), 

          "srcref"))) 

          return(no)

      }

    }

  }

  else test <- if (isS4(test)) 

    methods::as(test, "logical")

  else as.logical(test)

  ans <- test

  ok <- !is.na(test)

  if (any(test[ok]))

    ans[test & ok] <- rep(yes, length.out = length(ans))[test & ok]


  if (any(!test[ok])) 

    ans[!test & ok] <- rep(no, length.out = length(ans))[!test & ok]


  ans

}

That's why Hadley implemented his own if_else function. Your one if in f2 is substituted to many of in f1. And the last part is two separated actions for 'No' and 'Yes'.
So you can write your own ifelse function (for your own purposes) which will be much faster than the built-in

And the winner is

f3 = function(x, Len)

{

  rslt=rep("foo", Len)

  rslt[which(x==1, arr.ind = T)]="bar"

  return(rslt)

}

—
Kind regards,
Mittyri

Complete thread:

R Inferno Helmut 2019-04-26 16:03
- full conditions! mittyri 2019-04-26 16:20
  - full conditions! Helmut 2019-04-26 16:41
  - full conditions! d_labes 2019-04-27 14:29
    - magik of R implicit return mittyri 2019-04-27 22:23
      - magik of R implicit return ElMaestro 2019-04-27 22:34
        
        implicit return? d_labes 2019-04-28 19:36
        
        implicit return? ElMaestro 2019-04-28 20:36
        implicit return? Helmut 2019-04-28 20:50
        
        implicit return? ElMaestro 2019-04-28 21:16
        
        implicit return? Helmut 2019-04-28 23:38
        
        implicit return? ElMaestro 2019-04-29 09:40
        
        implicit return? Helmut 2019-04-29 10:41
        
        implicit return? ElMaestro 2019-04-29 12:55
        
        built-in ifelsemittyri 2019-04-30 13:05