matrix from list

The '[[' only returns a single element from a data structure

I know but that is precisely what I find arbitrary.

Anyway you are right that it would still return the kind of object, only 
subsetted, which is not I want. As someone kindly pointed out to me 
offline, besides the unlist trick posted before, you can also achieve the 
desired result with

   m <- as.matrix(l)
   dimnames(m) <- NULL

-- O.L.