Check out plyr: http://had.co.nz/plyr/
On Wed, Apr 15, 2009 at 2:03 PM, Lane, Jim <jim.l...@rbc.com> wrote: > Hi, All > > Forgive me if this is a stupid newbie question. I'm having no luck > googling an answer to this, probably because I don't know the right R > terminology to frame my question. I want to know how to run an R > function on each combination of the values of 2 or more variables. In > SAS-speak this is multiple "BY variables" or "CLASS variables". > > In R I've figured out how to do what I want with one by value. > > by(mf,mf$centre,summary) > > Centre is one of the columns in the data frame "mf" which looks like > this: > > names(mf) > [1] "centre" "complex" "appl" "pool" "month" "alloc_gb" > > I'd like to analyze, for example, by complex within centre. This has a > manageable number of combinations: > > table(mf$centre,mf$complex) > > A B C D E F G H > I J K L > B 0 0 0 0 0 0 0 0 0 > 0 0 60574 0 > G 44 209 0 94613 0 156 0 2541 0 > 748 0 0 215511 > O 0 0 0 0 0 0 3446 0 676 > 0 84400 0 0 > Q 0 0 298 0 66277 0 0 0 0 > 0 0 0 0 > > In SAS what I'm after is something like: > > Proc summary nway; > class centre complex; > var alloc_gb; > output out=s sum=; > run; > > How do I get something similar in R? > > Jim Lane > Capacity Planner > RBC Financial Group > 315 Front St W > 6th Floor - H14 > Toronto, Ontario CANADA > M5V 3A4 > 416-348-6024 > > Display of superior knowledge is as great a vulgarity > as display of superior wealth - greater indeed, inasmuch > as knowledge should tend more definitely than wealth > towards discretion and good manners. > > - H. W. Fowler, Modern English Usage > > > _______________________________________________________________________ > > This e-mail may be privileged and/or confidential, and the sender does not > waive any related rights and obligations. > Any distribution, use or copying of this e-mail or the information it > contains by other than an intended recipient is unauthorized. > If you received this e-mail in error, please advise me (by return e-mail or > otherwise) immediately. > > Ce courrier électronique est confidentiel et protégé. L'expéditeur ne renonce > pas aux droits et obligations qui s'y rapportent. > Toute diffusion, utilisation ou copie de ce message ou des renseignements > qu'il contient par une personne autre que le (les) destinataire(s) désigné(s) > est interdite. > Si vous recevez ce courrier électronique par erreur, veuillez m'en aviser > immédiatement, par retour de courrier électronique ou par un autre moyen. > > [[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. > > -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tr.im/mikes_public_calendar ~ Certainty is folly... I think. ~ ______________________________________________ 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.
