(I'm resending this, because there seemed to be a problem with my previous 
attempt.)

I've been scratching my head over this one for too long.  I'm hoping 
someone out there can solve this riddle.

I have two vectors of characters, v1 and v2, both of length L, and two 
matrices of logicals, m1 and m2, both of dimension N*L.  The first matrix 
of logicals corresponds to the first vector of characters, and the second 
to the second.

The matrices are telling me which of the elements of v1 and v2 are 
selected, and for each of the L elements either a value from v1 is 
selected, a value from v2 is selected, or neither is selected (but both 
are never selected).  So, the two matrices never have a TRUE in the same 
place, i.e., m1 + m2 yields a matrix of 0s and 1s (no 2s).

What I would like to end up with is a list of length N, that has the 
selected elements of v1 and v2 meshed together in their original order.

Here's an example (using much smaller N and L than in my real data):

v1 <- LETTERS[1:6]
v2 <- letters[1:6]

m1 <- matrix(c(T, F, F, T, F, F, F, F, T, F, T, F, F, F, F, T, F, F), 
byrow=T, ncol=6)
m2 <- matrix(c(F, T, F, F, F, T, F, F, F, F, F, F, F, F, F, F, T, F), 
byrow=T, ncol=6)

v1
v2
m1
m2
m1+m2

Given these two vectors and two matrices, I want to end up with this list:

result <- list(c("A", "b", "D", "f"), c("C", "E"), c("D", "e"))
result

I'm using R for Windows version 2.9.0.

Thanks for your help.

Jean
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