Is this what you want?
> lapply(split(d, d$foo), function(x) colSums(x[,-1]))
$a
bar baz
2 40
$b
bar baz
8 21
$c
bar baz
85 2
$d
bar baz
3 4
>
On Tue, Mar 18, 2008 at 5:41 AM, Hans Ekbrand <[EMAIL PROTECTED]> wrote:
> Consider the following data.frame, d.
>
> d <- data.frame(c("a","b","c","d","b","a"), c(1,4,85,3,4,1), c(7,6,2,4,15,33))
> names(d) <- c("foo", "bar", "baz")
>
> To get the colsum of d[[2]] for the rows that have d$foo == "a" I know
> I can use
>
> colSums(subset(d, d[[1]] == "a", select = 2))
>
> But what is needed to get a list of colSums for d[[2]] for each factor
> of d$foo ? Can it be done without a for loop?
>
> --
> Hans Ekbrand (http://sociologi.cjb.net) <[EMAIL PROTECTED]>
> GPG Fingerprint: 1408 C8D5 1E7D 4C9C C27E 014F 7C2C 872A 7050 614E
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.6 (GNU/Linux)
>
> iD8DBQFH35xlfCyHKnBQYU4RAqItAKC4Ksiq/ZP0mK98+Bp9nCeVt4m95QCfWALV
> b8WM/M+ITG502zi0McHnV30=
> =/dm6
> -----END PGP SIGNATURE-----
>
> ______________________________________________
> 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.
>
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem you are trying to solve?
______________________________________________
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.
