Re: [R] identify an element in a column

2011-02-22 Thread Ivan Calandra
Another way is with ifelse: z<-data.frame(x,y) z$y2 <- ifelse(z$x==5,z$y-1,z$y) HTH, Ivan Le 2/22/2011 18:27, Erik Iverson a écrit : Is this what you mean? z[which(z[,"x"] == 5) - 1, "y"] ?which is probably what you're looking for... Hongwei Dong wrote: Hi, R users, I'm wondering if I can

Re: [R] identify an element in a column

2011-02-22 Thread Joshua Wiley
Hi Gary, Another possibility besides Erik's (although I suspect his is what you are really after): ## easier way to data z <- cbind(x = 1:10, y = 11:20) z[z[,"x"] == 5, "y"] - 1 ## To see what is "going on", break it into pieces ## logical; does column 'x' of 'z' equal 5? z[, "x"] == 5 ## all va

Re: [R] identify an element in a column

2011-02-22 Thread Jorge Ivan Velez
Hi Gary, Try transform(z, y = ifelse(x == 5, y-1, y)) HTH, Jorge On Tue, Feb 22, 2011 at 12:18 PM, Hongwei Dong <> wrote: > Hi, R users, > > I'm wondering if I can identify an element in a column by an element in > another column. For example: > > x<-1:10 > y<-11:20 > z<-cbind(x,y) > z > x

Re: [R] identify an element in a column

2011-02-22 Thread Dimitris Rizopoulos
try this: x <- 1:10 y <- 11:20 z <- cbind(x, y) ind <- x == 5 z[ind, "y"] <- z[ind, "y"] - 1 z I hope it helps. Best, Dimitris On 2/22/2011 6:18 PM, Hongwei Dong wrote: Hi, R users, I'm wondering if I can identify an element in a column by an element in another column. For example: x<-1:

Re: [R] identify an element in a column

2011-02-22 Thread Erik Iverson
Is this what you mean? z[which(z[,"x"] == 5) - 1, "y"] ?which is probably what you're looking for... Hongwei Dong wrote: Hi, R users, I'm wondering if I can identify an element in a column by an element in another column. For example: x<-1:10 y<-11:20 z<-cbind(x,y) z x y [1,] 1 11 [

[R] identify an element in a column

2011-02-22 Thread Hongwei Dong
Hi, R users, I'm wondering if I can identify an element in a column by an element in another column. For example: x<-1:10 y<-11:20 z<-cbind(x,y) z x y [1,] 1 11 [2,] 2 12 [3,] 3 13 [4,] 4 14 [5,] 5 15 [6,] 6 16 [7,] 7 17 [8,] 8 18 [9,] 9 19 [10,] 10 20 What I want to do i