Hi,
OK, yes, it does require some explanation...
What is the difference between your examples 2 and 3, where the first
has the formula given explicitly, and the second has the formula
assigned to the object? As you said, case 2 works while case 3 fails.
2. with(c(newdata,obj...@data),model.matri
that seems to work, thank you.
would anyone care to explain *why* it works ... ? or where
I could go to read more about why it works ... ?
cheers
Ben Bolker
Felix Andrews wrote:
> how about...
>
> nrow(with(cc, model.matrix(params, data=environment(
>
> cheers
> -Felix
>
> 2009/
how about...
nrow(with(cc, model.matrix(params, data=environment(
cheers
-Felix
2009/8/10 Ben Bolker :
> I am having difficulty with evaluation/environment construction
> for a formula to be evaluated by model.matrix(). Basically, I
> want to construct a model matrix that first looks in "n
I am having difficulty with evaluation/environment construction
for a formula to be evaluated by model.matrix(). Basically, I
want to construct a model matrix that first looks in "newdata"
for the values of the model parameters, then in "obj...@data".
Here's what I've tried:
1. model.matrix(~
