Replacing occurrences of a number in multiple columns of data frame with another value in R

Question

ETA: the point of the below, by the way, is to not have to iterate through my entire set of column vectors, just in case that was a proposed solution (just

Answer 1

Just for continuity

    data[,2:3][ data[,2:3] == 4 ] <- 10

But it looks ugly, So do it in 2 steps is better.