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rforcats

fct_recode replace level by NA

I am trying to substitute all "a" in a R factor variable by a NA character using forcats::fct_recode. This is what i tried:

fct <- forcats::as_factor(c("a", "b"))
fct %>% forcats::fct_recode("c" = "a") #works
fct %>% forcats::fct_recode(NA = "a") #error
fct %>% forcats::fct_recode(NA_character_ = "a") #error

Is there a way to achieve my goal with fct_recode?

Solution

  • You need to use backticks to turn the values to NA :

    x1 <- fct %>% forcats::fct_recode(`NA` = "a") 
x1
#[1] NA b 
#Levels: NA b

    However, note that although this "looks" like NA it is not real NA. It is string "NA".

    is.na(x1)
#[1] FALSE FALSE

x1 == 'NA'
#[1]  TRUE FALSE

    To make it real NA replace it to NULL.

    x2 <- fct %>% forcats::fct_recode(NULL = "a")
x2
#[1] <NA> b   
#Levels: b

is.na(x2)
#[1]  TRUE FALSE