[R] sweep by levels of a factor
Hi, I'd appreciate help with this. I have a data matrix with one column, called f in the example below, a factor. I'd like to subtract the means from each of other columns for each level of the factor. That is, in the example, to go from the first matrix below to the second. I know SWEEP will take out means, but I want to do this for each level of the factor. fx 1 2 1 0 2 0 2 4 2 2 f xnew 11 1 -1 2 -2 22 2 0 Thanks [[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.
Re: [R] sweep by levels of a factor
Thank you very much, Tony L. On 18 November 2010 14:02, Lancaster, Anthony anthony_lancas...@brown.eduwrote: Hi, I'd appreciate help with this. I have a data matrix with one column, called f in the example below, a factor. I'd like to subtract the means from each of other columns for each level of the factor. That is, in the example, to go from the first matrix below to the second. I know SWEEP will take out means, but I want to do this for each level of the factor. fx 1 2 1 0 2 0 2 4 2 2 f xnew 11 1 -1 2 -2 22 2 0 Thanks [[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.
Re: [R] sweep by levels of a factor
Many thanks for your most helpful answers. Tony Lancaster On 18 November 2010 20:28, David Winsemius dwinsem...@comcast.net wrote: On Nov 18, 2010, at 1:23 PM, Henrique Dallazuanna wrote: Try this also: x$x - ave(x$x, x$f) Could also use scale for only its centering capacities: unlist( tapply(fx$x, fx$f, scale, scale=FALSE) # default for center == TRUE ) 11 12 21 22 23 1 -1 -2 2 0 ... but looking at the code for ave and for tapply makes me think ave would win in a foot race. scale() has other capacities that make its availability useful. -- David. On Thu, Nov 18, 2010 at 12:02 PM, Lancaster, Anthony anthony_lancas...@brown.edu wrote: Hi, I'd appreciate help with this. I have a data matrix with one column, called f in the example below, a factor. I'd like to subtract the means from each of other columns for each level of the factor. That is, in the example, to go from the first matrix below to the second. I know SWEEP will take out means, but I want to do this for each level of the factor. fx 1 2 1 0 2 0 2 4 2 2 f xnew 11 1 -1 2 -2 22 2 0 Thanks [[alternative HTML version deleted]] David Winsemius, MD West Hartford, CT [[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.
