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Create design matrix

3 messages · Bond, Stephen, Justin Haynes, Bert Gunter

#
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
#
?expand.grid
Var1 Var2
1    M    Y
2    F    Y
3    M    O
4    F    O
Justin
On Thu, Nov 3, 2011 at 10:56 AM, Bond, Stephen <Stephen.Bond at cibc.com> wrote: