Dear Alex, I think you want to use apply()
ij <- expand.grid(i = seq_len(dimx),j = seq_len(dimy)) Powermap <- apply(ij, 1, function(x){ Pr(x, c(PRX, PRY), f) }) Best regards, Thierry ---------------------------------------------------------------------------- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek team Biometrie & Kwaliteitszorg Gaverstraat 4 9500 Geraardsbergen Belgium Research Institute for Nature and Forest team Biometrics & Quality Assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 thierry.onkel...@inbo.be www.inbo.be To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey > -----Oorspronkelijk bericht----- > Van: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] Namens Alaios > Verzonden: woensdag 27 april 2011 11:37 > Aan: R-help@r-project.org > Onderwerp: [R] Assignments inside lapply > > Dear all I would like to ask you if an assignment can be done > inside a lapply statement. > > For example > > I would like to covert a double nested for loop > > for (i in c(1:dimx)){ > for (j in c(1:dimy)){ > Powermap[i,j] <- Pr(c(i,j),c(PRX,PRY),f) > } > } > > to something like that: > > > ij<-expand.grid(i=seq(1:dimx),j=(1:dimy)) > > unlist(lapply(1:nrow(ij),function(rowId) { return > (Powermap[i,j]<-Pr(c(ij$i[rowId],ij$j[rowId]),c(PRX,PRY),f)) })) > > > as you can see lapply does not return nothing as the > assignment is done inside the function. Would that work > correctly? What are the cases such a statement will misfunction? > > I would like to thank you in advace for your help. > > Best Regards > Alex > > ______________________________________________ > 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.