How to swap the values in two columns in R?

Question

V1    V2
 5     6
 4     4
 2     5

How would I swap the values in these two column vectors. So that the outcome would be:

V1    V2
 6     5
 4     4
 5     2

Answer 1

the easiest way to do this:

tmp <- df[1]
df[1] <- df[2]
df[2] <- tmp