Try this:

 xtabs(value ~ city + brand, mydf)

On Wed, Nov 3, 2010 at 6:23 PM, Dimitri Liakhovitski <
dimitri.liakhovitski@gmail.com> 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
>
> ______________________________________________
> 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.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

