r - Select first element of nested list

Question

Let's say I have a list like this:

x = list(list(1,2), list(3,4), list(5,6))

I would like a list that contains only the first elements of the nested list. I can do this by returning another list like so

x1 = lapply(x, function(l) l[[1]])

Is there shortcut notation for this?

Answer 1

Not much of a shortcut, but you can do this:

lapply(x, `[[`, 1)
# [[1]]
# [1] 1
#
# [[2]]
# [1] 3
#
# [[3]]
# [1] 5