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

Here's another answer. Assuming you mean test2 where you write test3, note that 'test2<5' is a logical vector. The minimum value will be FALSE. The maximum value (TRUE) is what you want:

> apply(test2<5,2,which.max)
[1] 3 4

Note that this is not correct if the maximum value is not TRUE.