[R] return one vector that is the sum of a list of vectors

[Bert Gunter]

?get
?rowSums
?rowsum

a "group" is not a defined data structure in R, btw. You have a much
better chance of getting precise answers if you ask precise questions.
See  the Posting Guide.

-- Bert

On Sun, Apr 8, 2012 at 9:01 PM, Frank Tamborello <frank.tambo at gmail.com> wrote:
> Dear R Help,
>
> I am attempting to write a function that  takes a list of variable groups and a vector of numbers (e.g., "jtsv" would indicate one group of variables, "jtsv1", "jtsv2", etc, each of which name a variable in a data frame), and returns a list of variable group sums. For example, given list("jtsv", "ptsv") and c(1:10), where jtsv1, etc, are all numeric vectors of the same length, the function should return a list of jtsv and ptsv, where
> jtsv <- jtsv1 + jtsv2 + jtsv3 + jtsv4 + jtsv5 + jtsv6 + jtsv7 + jtsv8 + jtsv9 + jtsv10
> ptsv <- ptsv1 + ptsv2 + ptsv3 + ptsv4 + ptsv5 + ptsv6 + ptsv7 + ptsv8 + ptsv9 + ptsv10
>
> So far I've used a for loop to paste together the names of the variables as character vectors, so that I can at least name the variables that I want to get, but I'm stuck on how to add together the numeric vectors that those character vectors are ultimately supposed to name. It seems like I should be able to map the primitive "+" operator onto a list or vector that contains the variable names. If that's a good way to go, what would that look like? Or if that's not a good way to go, would someone please point me in a good direction?
>
> Sincerely,
> Frank Tamborello
>
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm