Filtering the table based on rowname

1. I do have a list of elements in ab,

   ab <- list("M","O","E","P","Q","S","T","N","V","R")
   

2. In other list tb, is a list of 2*2 tables like,

   Sample data set,

   n <- c("M", "N", "O")
   tb <- lapply(1:10, function(i)matrix(sample(4), 2, 2, 
                                        dimnames=list(n[sample(3,2)], 
                                                      n[sample(3,2)])))
   names(tb) <- paste(1:10)
   

3. We only need to filter those tables in which the rowname of 1st table in the list tb has 1st element in the list ab , 2nd table has 2nd element and so on. The number of elements in both lis开发者_运维技巧t ab and tb are the same.

4. How will I match the rownames of the tables in the list with the list of elements?

> is.in <- vector(len=length(ab))
> for(i in 1:length(ab) ) { is.in[i] <- ab[i] %in% rownames(tb[[i]])}
> is.in
 #[1]  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE

Most of those ab-letters were not in the NMO list so I just checked to see if I were missing some:

 > tb[[8]] N M
O 1 4
M 2 3

But ab[8] = "N" is not in the rownames of tb[[8]]