how to assign column names to dataframe in r code example

Example 1: r set dataframe column names

R> X <- data.frame(bad=1:3, worse=rnorm(3))
R> X
  bad     worse
1   1 -2.440467
2   2  1.320113
3   3 -0.306639
R> colnames(X) <- c("good", "better")
R> X
  good    better
1    1 -2.440467
2    2  1.320113
3    3 -0.306639

Example 2: r set dataframe column names

R> colnames(X)[2] <- "superduper"