I am looking for a way to create a vector which contains the second element of
every vector in the list. However, not every vector has two components, so I
need to generate an NA for those missing. For example, I have created the
following list:
lst <- list(c("a", "b"), c("c"), c("d", "e"), c("f", "g"))
> lst
[[1]]
[1] "a" "b"
[[2]]
[1] "c"
[[3]]
[1] "d" "e"
[[4]]
[1] "f" "g"
I would like the output to be the following:
> output
[1] "b" NA "e" "g"
I know I can accomplish this using a for loop, but I am wondering if there's a
simple and neat way of getting this done in one step?
Thanks in advance.
- Andrew
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