Getting index of first occurrence of a value in every column of a matrix

Question

If I have a single vector, I can get the 1st occurrence which is below a value:

test <- c(0.5,0.8,0.1,0.08,0.06,0.04)
which(test<0.1)[1]    

Answer 1

As noted by Matthew, which.max does not return the correct value if there's no value <5 in a column (it returns 1, whereas the correct value is "nothing"). The match function is nice to handle this case:

> test2 <- matrix(c(5,8,3,4, 7,5,6,7), ncol=2)
> apply(test2<5, 2, which.max)
[1] 3 1
> apply(test2<5, 2, function(x) match(TRUE, x))
[1]  3 NA