Thanks for the clue. Actually the trouble comes when refering to a data.frame. If I use the matrix from the data.frame (matrix(mydataframe)), everything goes smoothly...
So I wrote: indices<-which(myforetbin > 0,arr.ind=T) myforetbin<-as.matrix(myforetbin) myforetbin[indices]<-1 myforetbin<-as.data.frame(myforetbin) It works but I wonder if there are no more simple ways... All the best, Patrick ----- Original Message ----- From: "Liaw, Andy" <[EMAIL PROTECTED]> To: "'Patrick Giraudoux'" <[EMAIL PROTECTED]>; "r-help" <[EMAIL PROTECTED]> Sent: Saturday, October 09, 2004 3:00 PM Subject: RE: [R] which() and value replacement in a matrix > Use the index vector directly, rather than breaking it up: > > > x <- matrix(sample(30), 10, 3) > > idx <- which(x > 25, arr.ind=TRUE) > > idx > row col > [1,] 6 1 > [2,] 9 1 > [3,] 4 2 > [4,] 6 2 > [5,] 4 3 > > x[idx] <- 999 > > x > [,1] [,2] [,3] > [1,] 7 14 16 > [2,] 20 24 8 > [3,] 17 18 11 > [4,] 19 999 999 > [5,] 23 4 15 > [6,] 999 999 5 > [7,] 21 9 12 > [8,] 22 2 3 > [9,] 999 13 1 > [10,] 6 10 25 > > HTH, > Andy > > > From: Patrick Giraudoux > > > > Hi, > > > > I cannot go through the archives with which() as key-word... > > so common. Though I am sure to have seen something about this subject > > in the past could somebody put me on the track. I have a > > matrix (actually a data.frame) in which I would replace the > > non-null values > > by 1. > > > > I tried the following: > > > > indices<-which(myforetbin > 0,arr.ind=T) > > myforetbin[indices[,1],indices[,2]]<-1 > > > > and get the message: > > > > > myforetbin[indices[,1],indices[,2]]<-1 > > Error in "[<-.data.frame"(`*tmp*`, indices[, 1], indices[, > > 2], value = 1) : > > duplicate subscripts for columns > > > > I get the same with > > > > myforetbin[indices]<-1 > > > > However, with: > > > > myforetbin[indices] > > > > I well get a vector with the corresponding non-null values. > > > > Can somebody put me on the track? > > > > All the best, > > > > Patrick > > > > ______________________________________________ > > [EMAIL PROTECTED] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > > > > ------------------------------------------------------------------------------ > Notice: This e-mail message, together with any attachments, contains information of > Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system. > ------------------------------------------------------------------------------ ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
