if is.na in r code example

Example 1: if not na in r

which( !is.na(p), arr.ind=TRUE)

Example 2: if not na in r

> apply(p, 1, function(x) which(!is.na(x)) )
[[1]]
[1] 2 3

[[2]]
[1] 4 7

[[3]]
integer(0)

[[4]]
[1] 5

[[5]]
integer(0)