How to change name of factor levels?

Question

training set

trainSample <- cbind(data[1:980,1], data[1:980,2]) cl <-
factor(c(data[1:980,3]))

test set

Answer 1

use forcats package.

a <- factor(rep(c(1,2,1),50))

fct_collapse(a,c = c("1"),`not-c` = c("2"))