r - replace multiple values in a column for a single one

Question

I have a rather basic question. I have several values in a column that I would like to replace for a single one, for instance:

a<-data.frame(T=LETTERS[5:20],V=rnorm(16,10,1))

and I would like to change all "E", "S", "T" in T for "AB", so I tried

a[a$T==c("E","S","T")]<-"AB"

and it gives me several warnings, and ends up replacing all to "AB"

I think it has something to do with levels and level's labels but I was not able to replace only some of the values, I would have to re-label each. Sorry for the trouble, and thanks for any help!

Answer 1

You can use function recode() from library car to change values also for the factors.

library(car)
a$T<-recode(a$T,"c('E','S','T')='AB'")

If you need to replace different values with different other values then all statements can be written in one function call.

recode(a$T,"c('E','S','T')='AB';c('F','G','H')='CD'")