on 01/14/2009 03:50 PM Lo, Ken wrote: > Dear list, > > I have a list of number sequences. Each number sequence has different > numbers of elements. Is there a quick way (other than to iterate > through the entire list) way to coerce list to matrix with NAs filling > in the short sequences? > > An example of what I mean is this: > > A <- list(c(3,2,3),c(6,5)) > > I'd like to get A so that it is > > 3 2 3 > 6 5 NA
A "quick and dirty" two step approach: # Get the max length of the vectors in 'A' L.max <- max(sapply(A, length), na.rm = TRUE) # Now extract each vector from 'A', appending an appropriate # number of NA's to fill out the vector > t(sapply(A, function(x) c(x, rep(NA, L.max - length(x))))) [,1] [,2] [,3] [1,] 3 2 3 [2,] 6 5 NA HTH, Marc Schwartz ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.