Thanks a lot! Yes - I just found the reshape package too - and guess what, my math was wrong! reshape2 seems like the more up-to-date version of reshape.
Wonder what's faster - xtabs or dcast... Dimitri On Wed, Nov 3, 2010 at 4:32 PM, Henrique Dallazuanna <[email protected]> wrote: > Try this: > > xtabs(value ~ city + brand, mydf) > > On Wed, Nov 3, 2010 at 6:23 PM, Dimitri Liakhovitski > <[email protected]> wrote: >> >> Hello! >> >> I have a data frame like this one: >> >> >> mydf<-data.frame(city=c("a","a","a","a","a","a","a","a","b","b","b","b","b","b","b","b"), >> brand=c("x","x","y","y","z","z","z","z","x","x","x","y","y","y","z","z"), >> value=c(1,2,11,12,111,112,113,114,3,4,5,13,14,15,115,116)) >> (mydf) >> >> What I need to get is a data frame like the one below - cities as >> rows, brands as columns, and the sums of the "value" within each >> city/brand combination in the body of the data frame: >> >> city x y z >> a 3 23 336 >> b 7 42 231 >> >> >> I have written a code that involves multiple loops and subindexing - >> but it's taking too long. >> I am sure there must be a more efficient way of doing it. >> >> Thanks a lot for your hints! >> >> >> -- >> Dimitri Liakhovitski >> Ninah Consulting >> www.ninah.com >> >> ______________________________________________ >> [email protected] 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. > > > > -- > Henrique Dallazuanna > Curitiba-Paraná-Brasil > 25° 25' 40" S 49° 16' 22" O > -- Dimitri Liakhovitski Ninah Consulting www.ninah.com ______________________________________________ [email protected] 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.
