thanks everyone. I will try them. Best Wishes Nan
----- Original Message ---- From: Steven McKinney <smckin...@bccrc.ca> To: Hey Sky <heyskywal...@yahoo.com>; "r-help@r-project.org" <r-help@r-project.org> Sent: Mon, August 2, 2010 10:56:32 PM Subject: RE: [R] how to do a IF ELSE in a matrix format Here's one way: edu[edu[, 1] < 0.5, 2] <- 1 > set.seed(1) > edu<-matrix(0,1000,2) > edu1<-runif(1000,0,1) > edu[,1]<-edu1 > head(edu) [,1] [,2] [1,] 0.2655087 0 [2,] 0.3721239 0 [3,] 0.5728534 0 [4,] 0.9082078 0 [5,] 0.2016819 0 [6,] 0.8983897 0 > edu[edu[, 1] < 0.5, 2] <- 1 > head(edu) [,1] [,2] [1,] 0.2655087 1 [2,] 0.3721239 1 [3,] 0.5728534 0 [4,] 0.9082078 0 [5,] 0.2016819 1 [6,] 0.8983897 0 > Steven McKinney > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On >Behalf Of Hey Sky > Sent: August-02-10 6:17 PM > To: r-help@r-project.org > Subject: [R] how to do a IF ELSE in a matrix format > > Hey, Rers > > I am new to R and this question may has been asked many times or a very old > one. I have checked > > the archive but found nothing (maybe I used the wrong key words). any advise is > appreciated > > the question is: > > I try to replace a col vector with some other values, see > > edu<-matrix(0,1000,2) > > edu1<-runif(1000,0,1) > edu[,1]<-edu1 > > the colum vector edu[,1] would have value between 0 and 1. if I want to > replace the value of edu[,2] > > to 1 if edu[,1] less than 0.5, how to do it in the form of matrix but not under > a loop structure? > > I have tried: > > if (edu[,1]>=0.5) edu[,2]=1 > > there is only the first 0.5 have been done but not all the others. thanks for > any kind answer. > > Nan > from Montreal > > > > ______________________________________________ > 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.