Negation of %in% in R

r match negation
Qaswed picture Qaswed · Jul 13, 2016 · Viewed 33.8k times · Source

Is there a short negation of %in% in R like !%in% or %!in%?

Of course I can negate c("A", "B") %in% c("B", "C") by !(c("A", "B") %in% c("B", "C")) (cf. this question) but I would prefere a more straight forward approach and save a pair of brackets (alike presumably most people would prefer c("A", "B") != c("B", "C") over !(c("A", "B") == c("B", "C"))).

Answer

catastrophic-failure picture catastrophic-failure · Jul 13, 2016

No, there isn't a built in function to do that, but you could easily code it yourself with 

`%nin%` = Negate(`%in%`)

Or

`%!in%` = Negate(`%in%`)

See this thread and followup discussion: %in% operator - NOT IN

Also, it was pointed out the package Hmisc includes the operator %nin%, so if you're using it for your applications it's already there.

library(Hmisc)
"A" %nin% "B"
#[1] TRUE
"A" %nin% "A"
#FALSE

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