Feature request: argument in fct_recode to reorder based on sequence

[rpodcast]

I struggled with making a clear title of this feature request, but here is my idea. I really like using the fct_recode function to change the levels of factors (especially for plotting purposes) but I noticed that the new version of the factor keeps the same order of levels as the original version before the recoding using fct_recode even though I specified the order different in the arguments to fct_recode. It would be nice to have an extra parameter in fct_recode to let the order be dictated by how the levels are given in the call. Here's a minimal example using the forcats CRAN release of 0.1.1:

library(forcats)
data(diamonds)

# show order of cut
levels(diamonds$cut)
# [1] "Fair"      "Good"      "Very Good" "Premium"   "Ideal"  

# recode levels using fct_recode
diamonds2 <- diamonds %>%
  mutate(cut2 = fct_recode(cut, "Very Great" = "Very Good", "Great" = "Good", "Really Ideal" = "Ideal", "Really Premium" = "Premium", "Bad" = "Fair"))

# show order of cut2
levels(diamonds2$cut2)
# [1] "Bad"            "Great"          "Very Great"     "Really Premium" "Really Ideal"  

[krlmlr]

Does fct_rev() and/or fct_relevel() work for you?

[epruesse]

Just ran into the same issue. I've got some data with nonsensically named classes and want to impose both new names and a sensible order at the same time.

Since google led me here ... could you briefly explain a good way to do that? I.e. have a fct_recode that also relevels the factor in order of the arguments provided?

[epruesse]

In answer to myself:

fct_reorg <- function(fac, ...) {
  fct_recode(fct_relevel(fac, ...), ...)
}

Works like this:

> x<-factor(c("a","b","c"))
> x
[1] a b c
Levels: a b c
> fct_recode(x, B="b", C="c")
[1] a B C
Levels: a B C
> fct_reorg(x, B="b", C="c")
[1] a B C
Levels: B C a

[sjackman]

I ran into this same question recently.

relevel = c(
  "Alfa" = "A",
  "Bravo" = "B",
  "Charlie" = "C",
  "Delta" = "D")

after <- before %>%
  mutate(
    Var1 = fct_recode(fct_relevel(Var1, !!!relevel), !!!relevel),
    Var2 = fct_recode(fct_relevel(Var2, !!!relevel), !!!relevel))