Hi, I was irritated about your printed last row of A, which apart from definition contains a 20. Anyway, how about this:
y<-x<-rep(NA,nrow(A)) #its not clear, whether multiple values of 100 can occur in a single #row, and what to do, when 100 is found before and after 20, so you may #alter the indexing as you need: ind<-subset(merge(which(A==20,arr.ind=T),which(A==100,arr.ind=T),by="row",all.x=T),col.x<col.y|is.na(col.y)) x[ind$row]<-ind$col.x y[ind$row]<-ind$col.y x y which places an NA in x and y for all "no shows". I did not get the logic behind setting x[3] to ">5" but x[5] to NA (same for y[3], y[4]), so this is left for you to implement. cheers. Am 10.08.2011 08:15, schrieb gallon li: > I have a following matrix and wish to define a variable based the variable > > A=matrix(0,5,5) > A[1,]=c(30,20,100,120,90) > A[2,]=c(40,30,20,50,100) > A[3,]=c(50,50,40,30,30) > A[4,]=c(30,20,40,50,50) > A[5,]=c(30,50,NA,NA,100) >> A > [,1] [,2] [,3] [,4] [,5] > [1,] 30 20 100 120 90 > [2,] 40 30 20 50 100 > [3,] 50 50 40 30 30 > [4,] 30 20 40 50 50 > [5,] 30 20 NA NA 100 > I want to define two variables: > > X is the first column in each row that is equal to 20, for example, for the > first row, I need X=2; 2nd row, X=3; 3rd row, X>5; 3th row, X=2, 5th row, > X=NA; > > Y is then the first column in each row that is equal to 100 if before this a > 20 has been reached, for example, for the first row, Y=3; 2nd row, Y=5; 3rd > row, Y=NA, 4th row, Y>5; 5th row, Y=NA. > > the matrix may involve NA as well. > > How can I define these two variables quickly? (When X>5 or Y>5, we can > arbitrarily assign a value 6, and this is different from being NA) > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. -- Eik Vettorazzi Department of Medical Biometry and Epidemiology University Medical Center Hamburg-Eppendorf Martinistr. 52 20246 Hamburg T ++49/40/7410-58243 F ++49/40/7410-57790 ______________________________________________ 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.
