Your example has one more element in 'ind' than 'example' and that is what causes the error, but this should be close.
> #sample data > set.seed(100) > example = list(letters[1:10], letters[1:10], letters[1:10]) > ind = list(as.logical(sample(0:1, 10, rep=TRUE)), + as.logical(sample(0:1, 10, rep=TRUE)), + as.logical(sample(0:1, 10, rep=TRUE)), + as.logical(sample(0:1, 10, rep=TRUE))) > > mapply(function(a,b)a[b], example, ind) [[1]] [1] "c" "g" "i" [[2]] [1] "a" "b" "e" "f" "j" [[3]] [1] "a" "b" "c" "d" "g" "h" "i" [[4]] [1] "b" "d" "e" "f" "h" "i" Warning message: In mapply(function(a, b) a[b], example, ind) : longer argument not a multiple of length of shorter > On Fri, Jun 26, 2009 at 2:27 PM, Greg Hirson <ghir...@ucdavis.edu> wrote: > Dear list, > > I have two lists: one with data and one with TRUE/FALSE values for data I > want to further analyze (see example below). I have been able to use a for > loop to extract the data that I want to keep, but think that there probably > exists a way to do it without a loop. Any ideas? > > #sample data > set.seed(100) > example = list(letters[1:10], letters[1:10], letters[1:10]) > ind = list(as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1, > 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE)), > as.logical(sample(0:1, 10, rep=TRUE))) > > #loop method > for (i in 1:length(example)) print(example[[i]][ind[[i]]]) > > #result > [1] "c" "g" "i" > [1] "a" "b" "e" "f" "j" > [1] "a" "b" "c" "d" "g" "h" "i" > > > Thank you for the help. > > Greg > > -- > Greg Hirson > ghir...@ucdavis.edu > > Graduate Student > Agricultural and Environmental Chemistry > > 1106 Robert Mondavi Institute North > One Shields Avenue > Davis, CA 95616 > > ______________________________________________ > 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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? [[alternative HTML version deleted]] ______________________________________________ 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.
