tmp0 <- list(a=1, b=2, c=3) tmp0["b"] <- list(NULL) # single [, list(NULL), not double [[ and bare NULL str(tmp0) # List of 3 # $ a: num 1 # $ b: NULL # $ c: num 3
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Gonçalo Ferraz > Sent: Thursday, November 15, 2012 1:01 PM > To: r-help@r-project.org > Subject: [R] assigning NULL to a list element without changing the length of > the list > > Hi, > > I have a list: > > tmp0 <- list(a=1, b=2, c=3) > > And I realize that I can append a NULL element to the end of this list, just > by writing: > > length(tmp0) <- 4 > > Now, the question is, how can I assign NULL to one of the existing list > elements without > changing the length of the list? > > Please note I am working from inside a for loop that is working on one list > element at a > time and in some circumstances I want to > set one element to NULL. So, specifying the whole list again as in: > > tmp0 <- list(a=1,b=NULL,c=3) > > is not an option. > > But writing, say: > > tmp0 [[2]] <- NULL > > is not an option either, because it leaves me with a list of length 2. > > Is there a solution for this? > > Thank you > > ______________________________________________ > 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.
