Substring of all data frame elements

Question

Consider:

x = data.frame(c('ABCD', 'EFGH'), row.names=c('1A', '1B'))

I need a substring of each element in the data frame. Something like this:

substring(x, 2,4)

Answer 1

You could use sapply:

sapply(x, substring, 2, 4)

or, if you want to take only one specific column - say #1 - of the data frame:

substring(x[,1], 2, 4)