yes, it works, even if I do not really get how and why it's working the combination of logical results (could you provide some insights for that?)
moreover, and most of all, I was hoping for a compact solution because I need to deal with MANY columns (more than 40) in data frame with the same basic structure as the simplified example I posted thanks m ----- Messaggio originale ----- Da: "Bert Gunter" <bgunter.4...@gmail.com> A: "Massimo Bressan" <massimo.bres...@arpa.veneto.it> Cc: "r-help" <r-help@r-project.org> Inviato: Mercoledì, 22 novembre 2017 17:32:33 Oggetto: Re: [R] assign NA to rows by test on multiple columns of a data frame Do you mean like this: mydf <- within(mydf, { is.na(A)<- !A_flag is.na(B)<- !B_flag } ) > mydf A A_flag B B_flag 1 8 10 5 12 2 NA 0 6 9 3 10 1 NA 0 4 NA 0 1 5 5 5 2 NA 0 Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Nov 22, 2017 at 2:34 AM, Massimo Bressan < massimo.bres...@arpa.veneto.it> wrote: > > > Given this data frame (a simplified, essential reproducible example) > > > > > A<-c(8,7,10,1,5) > > A_flag<-c(10,0,1,0,2) > > B<-c(5,6,2,1,0) > > B_flag<-c(12,9,0,5,0) > > > > > mydf<-data.frame(A, A_flag, B, B_flag) > > > > > # this is my initial df > > mydf > > > > > I want to get to this final situation > > > > > i<-which(mydf$A_flag==0) > > mydf$A[i]<-NA > > > > > ii<-which(mydf$B_flag==0) > > mydf$B[ii]<-NA > > > > > # this is my final df > > mydf > > > > > By considering that I have to perform this task in a data frame with many > columns I’m wondering if there is a compact and effective way to get the > final result with just one ‘sweep’ of the dataframe? > > > > > I was thinking to the function apply or lapply but I can not properly > conceive how to… > > > > > any hint for that? > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.