On Dec 10, 2009, at 9:44 PM, Peng Yu wrote:
The following code returns a list with the 2nd element as NULL. I'm wondering what the best way to get rid of NULL element in an 'apply()'s result.lapply(1:3, function(x) {+ if(x==2) { + return(NULL) + } else { + return(x) + } + } + ) [[1]] [1] 1 [[2]] NULL [[3]] [1] 3
L <- list(1, NULL, 3) > L [[1]] [1] 1 [[2]] NULL [[3]] [1] 3 L[[2]] <- NULL > L [[1]] [1] 1 [[2]] [1] 3 The above is actually covered in the first R FAQ: http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-can-I-set-components-of-a-list-to-NULL_003f 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.
