I'm running into a strange problem. I have a vector of lists and I use unlist on them. Some of the elements in the vectors are NULL and unlist seems to be dropping them. How can I prevent this?
Here's a simple (non) working example showing this unwanted feature of unlist
a = c(list("p1"=2, "p2"=5),
list("p1"=3, "p2"=4),
list("p1"=NULL, "p2"=NULL),
list("p1"=4, "p2"=5))
unlist(a)
p1 p2 p1 p2 p1 p2
2 5 3 4 4 5