Does ave() do what you want? y. <- ave(x$value, x$x1, x$x2, FUN=function(x)x)
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Marius Hofert > Sent: Saturday, September 15, 2012 11:07 AM > To: R-help > Subject: [R] How to convert the output of tapply() so that it has the same > order as the > input? > > Hi, > > I try to apply a function to subsets of a data.frame. tapply() does the job, > but > the as output, I am looking for a vector (not an array/matrix) ordered in the > same way as the original data, so I can simply cbind the result to the > original > data.frame. Below is a minimal example. > > I know that there are packages that can do these things easier, but I'm > looking > for a fast solution not requiring additional packages. > > Cheers, > > Marius > > > ## data.frame > set.seed(1) > (x <- data.frame(x1=LETTERS[1:4], x2=1:2, value=runif(8))) > > ## apply a function to each subset combination of x1 and x2 > y <- tapply(x$value, x[,-3], function(x) x) > > ## (trials of) transforming the output to be of the same type and order as > x$value > (y. <- do.call(rbind, y)) # => wrong order > (y. <- do.call(cbind, y)) # => wrong order > > ## appending (that's the goal) > z <- x > z$value <- y. > > ______________________________________________ > 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.
