I am not sure that I understand but does something like this do what you want?
ec<-1:10 vec[vec==4] <- 100 vec <- 1:10 vec[ vec==4 | vec==8] <- 100 vec <- 1:10 aa <- 50 vec[vec==4] <- aa John Kane Kingston ON Canada > -----Original Message----- > From: marc_...@yahoo.fr > Sent: Sun, 18 Mar 2012 18:24:34 +0000 (GMT) > To: r-help@r-project.org > Subject: [R] assign a value to an element > > Assign can be used to set a value to a variable that has name as a value > of another variable. Example: > >> name<-"essai" >> assign(name, "plouf") >> essai > [1] "plouf" > > OK. > But how to do the same when it is only an element of a vector, data frame > and so on that must be changed. > >> vec<-1:10 >> vec > [1] 1 2 3 4 5 6 7 8 9 10 >> vec[4] > [1] 4 >> name<-"vec[4]" >> assign(name, 100) >> vec > [1] 1 2 3 4 5 6 7 8 9 10 > > The reason is probably here (from help of assign): > assign does not dispatch assignment methods, so it cannot be used to set > elements of vectors, names, attributes, etc. > > > I have found this solution: >> eval(parse(text=paste(name, "<-100", sep=""))) >> vec > [1] 1 2 3 100 5 6 7 8 9 10 > > Is-it the only way ? It is not very elegant ! > > Thanks a lot > > Marc > > __________________________________________________________ > Marc Girondot, Pr > > Laboratoire Ecologie, Systimatique et Evolution > Equipe de Conservation des Populations et des Communautis > CNRS, AgroParisTech et Universiti Paris-Sud 11 , UMR 8079 > Bbtiment 362 > 91405 Orsay Cedex, France > > Tel: 33 1 (0)1.69.15.72.30 Fax: 33 1 (0)1.69.15.73.53 > e-mail: marc.giron...@u-psud.fr > Web: http://www.ese.u-psud.fr/epc/conservation/Marc.html ____________________________________________________________ FREE 3D MARINE AQUARIUM SCREENSAVER - Watch dolphins, sharks & orcas on your desktop! ______________________________________________ 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.
