Given this factor variable:
library(tidyverse)
a <- factor(c(1,1,1,2,2), levels=c(1,2), labels=c("Male", "Female"))
I want this to error out because Females is not a valid level:
a %>% .[.=="Male"|.=="Females"]
How can I do that?
forcats::fct_match() errors when levels aren't present, so you can do:
library(forcats)
a <- factor(c(1,1,1,2,2), levels=c(1,2), labels=c("Male", "Female"))
a %>% .[fct_match(., c("Male", "Females"))]
#> Error in `fct_match()`:
#> ! All `lvls` must be present in `f`.
#> ℹ Missing levels: "Females"
a %>% .[fct_match(., c("Male", "Female"))]
#> [1] Male Male Male Female Female
#> Levels: Male Female