sapply(a, `[`, 1) On Wed, Aug 24, 2011 at 12:18 AM, Chee Chen <chee.c...@yahoo.com> wrote: > Dear All, > I would like to know, beside writing a function and then apply it to a list, > or using a for loop, whether there is a one-line command to do the following. > Suppose we have a list, each of whose components are numeric: >> a <- vector("list",3) >> a[[1]] <-c(1,2) >> a[[2]] <-c(3,4) >> a[[3]] <- c(5,6) >> a > [[1]] > [1] 1 2 > > [[2]] > [1] 3 4 > > [[3]] > [1] 5 6 > > Target: I would like to extract from each of its components the first entry > and store them into a vector, ie, to extract 1 from a[[1]], 3 from a[[2]], 5 > from a[[3]], and store 1,3,5 into a vector without using for loops. > Thank you, > Chee > [[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. >
______________________________________________ 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.