Question

I have the following matrices:

m = matrix(c(1:12), nrow=4)
p = matrix(c(2,7,11), nrow=1)

Per each column of m and p, I want to find the values in the columns of m which are less than the values in columns of p

p = 1 6 11 

m = 1 5 9
    2 6 10
    3 7 11
    4 8 12

So that I can get something like this:

ans = m[,] > p[,]

ans = 
    F F F
    T F F
    T T F
    T T T

(or something similar)

I have tried m[,] > p[,] and also set p to be a vector, but neither works.

Answer 1

lapply(1:length(p), function(x) m[p[x] > m[,x],x])
[[1]]
[1] 1

[[2]]
[1] 5 6

[[3]]
[1]  9 10