This is a bit simpler: > df$x_new <- ave(df$T, df$ID, FUN=function(x)x!=min(x)) > df ID T x x_new 1 1 1 0 0 2 1 2 1 1 3 1 3 1 1 4 2 1 0 0 5 2 4 1 1 6 3 3 0 0 7 3 5 1 1 8 3 6 1 1 9 3 8 1 1
Are you sure there are no ties for the minimum value? ---------------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77843-4352 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of William Dunlap > Sent: Tuesday, December 18, 2012 10:45 AM > To: Carlos Nasher; r-help@r-project.org > Subject: Re: [R] Set a zero at minimum row by group > > You should show what you tried with aggregate and tapply. > > You could use ave(): > > wm <- as.logical(ave(df$T, df$ID, FUN=function(x)x==min(x))) > > df$x_new <- df$x > > df$x_new[wm] <- 0 > > df > ID T x x_new > 1 1 1 1 0 > 2 1 2 1 1 > 3 1 3 1 1 > 4 2 1 1 0 > 5 2 4 1 1 > 6 3 3 1 0 > 7 3 5 1 1 > 8 3 6 1 1 > 9 3 8 1 1 > > (The as.logical is there because ave() coerces the logical output of > FUN to the type of df$T, numeric, and we need to convert it back to > logical.) > > Bill Dunlap > Spotfire, TIBCO Software > wdunlap tibco.com > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf > > Of Carlos Nasher > > Sent: Tuesday, December 18, 2012 6:10 AM > > To: r-help@r-project.org > > Subject: [R] Set a zero at minimum row by group > > > > Dear R Helpers, > > > > I'm struggling with a data preparation problem. I feel that it is a > quite > > easy task but I don't get it done. I hope you can help me with that. > > > > I have a data frame looking like this: > > > > ID <- c(1,1,1,2,2,3,3,3,3) > > T <- c(1,2,3,1,4,3,5,6,8) > > x <- rep(1,9) > > df <- data.frame(ID,T,x) > > > > >df > > ID T x > > 1 1 1 > > 1 2 1 > > 1 3 1 > > 2 1 1 > > 2 4 1 > > 3 3 1 > > 3 5 1 > > 3 6 1 > > 3 8 1 > > > > I want to manipulate the x column in a way that for each customer > (ID) at > > the minimum of T the x value is set to zero. The result should look > like > > this: > > > > ID T x x_new > > 1 1 1 0 > > 1 2 1 1 > > 1 3 1 1 > > 2 1 1 0 > > 2 4 1 1 > > 3 3 1 0 > > 3 5 1 1 > > 3 6 1 1 > > 3 8 1 1 > > > > I already tried the aggregate() and apply() function, but I don't get > the > > result I'm looking for. I would glad if you could help me out. > > > > Best regards, > > Carlos > > > > [[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. > > ______________________________________________ > 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.
