Applying gsub to various columns

Question

What is the most efficient way to apply gsub to various columns? The following does not work

x1=c(\"10%\",\"20%\",\"30%\")
x2=c(\"60%\",\"50%\",         


        

Answer 1

To add on docendo discimus' answer, an extension with non-adjacent columns and returning a data.frame:

x1 <- c("10%", "20%", "30%")
x2 <- c("60%", "50%", "40%")
x3 <- c(1, 2, 3)
x4 <- c("60%", "50%", "40%")

x <- data.frame(x1, x2, x3, x4)

x[, c(1:2, 4)] <- as.data.frame(apply(x[,c(1:2, 4)], 2,
                                         function(x) {
                                           as.numeric(gsub("%", "", x))}
))

> x
  x1 x2 x3 x4
1 10 60  1 60
2 20 50  2 50
3 30 40  3 40

> class(x)
[1] "data.frame"