[R] comparing two matrices

[Adrian Dusa]

Dear helpeRs,

I have two matrices:
mat1 <- expand.grid(0:2, 0:2, 0:2)
mat2 <- aa[c(19, 16, 13, 24, 8), ]

where mat2 is always a subset of mat1

I need to find the corersponding row numbers in mat1 for each row in mat2.
For this I have the following code:

apply(mat2, 1, function(x) {
    which(apply(mat1, 1, function(y) {
        sum(x == y)
        }) == ncol(mat1))
    })

The code is vectorized, but I wonder if there is a simpler (hence faster) 
matrix computation that I miss.

Thank you,
Adrian


-- 
Adrian Dusa
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