apply function to matrix

apply.function.to.matrix.R

> df <- data.frame(x=c("spam", "spam", "ham"), y=c("some mail", "some other mail", "some third mail"))
> add.string.func <- function(somestr) { paste("prefix-", somestr, "-postfix", sep = "") }
> df[1,]
     x         y
1 spam some mail
> df[,1]
[1] spam spam ham 
Levels: ham spam
> apply(X = df[1,], add.string.func, MARGIN = 1)
     1                         
[1,] "prefix-spam-postfix"     
[2,] "prefix-some mail-postfix"
> apply(X = as.matrix(df[,1]), add.string.func, MARGIN = 1)
[1] "prefix-spam-postfix" "prefix-spam-postfix" "prefix-ham-postfix"