r - How to filter a matrix by the value of another -

i have 2 matrices: m1 , m2.

m1:

    1   2   3   4   5 1  v11 v12 v13 v14 v15 2  v21 v22 v23 v24 v25 3  v31 v32 v33 v34 v35  4  v41 v42 v43 v44 v45 5  v51 v52 v53 v54 v55 

m2:

 x1, x2  1   1  1   2  1   4  2   2  2   3      2   5     

i keep m1 if rowname , colname found in m2, otherwise, write "na" location

e.g. result should be:

m1:

    1   2   3   4   5 1  v11 v12 na  v14  na 2  na  v22 v23  na v25 3  na  na  na  na  na  4  na  na  na  na  na 5  na  na  na  na  na 

so far tried use:

m1[!(rownames(m1) %in% m2$x1 & colnames(m1) %in% m1$x2)]<-na 

the result not right? suggestions?

in old answer thought op wanted select specific elements m1, based on m2. hong ooi's answer works if dimnames of m1 line with row , column indices, , m2 contains integers , not character values. here rough solution if not line up.

m1 <- matrix(c("v11","v21","v12","v22","v13","v23"),nrow=2,ncol=3) dimnames(m1) <- list(c("r2","r1"),c("c1","c2","c3")) m2 <- matrix(c("r1","r1","r2","c1","c3","c3"),nrow=3,ncol=2)  > m1    c1    c2    c3    r2 "v11" "v12" "v13" r1 "v21" "v22" "v23"  > m2      [,1] [,2] [1,] "r1" "c1" [2,] "r1" "c3" [3,] "r2" "c3"  temp <- matrix(true,nrow=nrow(m1),ncol=ncol(m1))  for(i in 1:nrow(m2)){   temp[which(rownames(m1)==m2[i,1]),which(colnames(m1)==m2[i,2])] <- false }  m1[temp] <- na  > m1    c1    c2 c3     r2 na    na "v13" r1 "v21" na "v23" 

old answer:

m1 <- matrix(c("v11","v21","v12","v22","v13","v23"),nrow=2,ncol=3)  > m1      [,1]  [,2]  [,3]  [1,] "v11" "v12" "v13" [2,] "v21" "v22" "v23"  m2 <- matrix(c(1,1,2,1,3,3),nrow=3,ncol=2)  > m2      [,1] [,2] [1,]    1    1 [2,]    1    3 [3,]    2    3  keep <- paste(paste0(m2[,1],m2[,2]),collapse="|") m1[!grepl(keep,m1)] <- na  > m1      [,1]  [,2] [,3]  [1,] "v11" na   "v13" [2,] na    na   "v23" 

or one-liner:

m1[!grepl(paste(paste0(m2[,1],m2[,2]),collapse="|"),m1)] <- na