?expand.grid   is what you're looking for, I think.
(which, I agree, is not something one could easily guess)

-- Bert

On Thu, Nov 3, 2011 at 10:56 AM, Bond, Stephen <Stephen.Bond@cibc.com>wrote:

> Greetings useRs,
>
> What is the easiest way to create a design matrix of several factor
> variables? Function gendata in Design seems to do that for a fitted model,
> but how to do that only on several factor vectors??
>
> The result should be a df with one row for each distinct combination of
> levels of factors eg for (M,F) (Y,O)
> We get
> M Y
> M O
> F Y
> F O
>
> In reality I will have more than 1000 rows so doing by hand not good.
> Maybe there is a way with "outer", but I couldn't see it.
> All the best to everybody.
>
> Stephen
>
> ______________________________________________
> 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.
>



-- 

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

	[[alternative HTML version deleted]]

