Finding pattern in one matrix to another matrix in R

Question

I have a matrix (V), which looks like this

         [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
[V1,]   37   15   30    3    4   11   35   31
[V2,]   44   31   45   30   24   39    1   18
[V3,]   39   49    7   36   14   43   26   24
[V4,]   45   31   26   33   12   47   37   15
[V5,]   23   27   34   29   30   34   17    4
[V6,]    9   46   39   34    8   43   42   37

I have another matrix (X)

         [,1] [,2] [,3] [,4] [,5] [,6] 
[X1,]   37   15   21    3    4   11   35   31
[X2,]   37   37   45   30   24   39    1   18
[X3,]   39   49    7   36   14   43   26   24
[X4,]   45   31   26   37   12   47   37   15
[X5,]   23   27   34   29   30   37   17    4
[X6,]    9   46   39   34    8   37   42   37

Now each row of matrix V should be matched with each row of matrix X to get a count matrix like

  [,V1] [,V2] [,V3] [,V4] [,V5] [,V6] [,V7] [,8]
[X1,]   7      
[X2,]   

To check the common numbers between X1 and V1??

How do I do it using R? Please suggest me some ideas

Answer 1

Here is one quick 'brute-force' way with apply

row.names(V) <- paste0("V",seq(6))
row.names(X) <- paste0("X",seq(6))

apply(V, 1, function(i){
  apply(X, 1, function(j){
    length(intersect(i, j))
    }
  )
})

   V1 V2 V3 V4 V5 V6
X1  7  1  0  3  1  1
X2  2  6  2  2  1  2
X3  0  2  8  1  0  2
X4  3  2  1  7  0  1
X5  3  1  0  1  7  2
X6  1  1  1  1  1  7

Answer 2

Use == to compare the elements of the two matrices. This will give you a matrix of logicals (TRUEs and FALSEs). You can then add up the the number of TRUEs in each row using apply().

apply(V==X, 1, sum)