[R] Problem with object inside a function

[Ronaldo Reis Junior]

Em Dom 20 Abr 2008, Ronaldo Reis Junior escreveu:
> Hi all,
>
> I have a problem with an object inside a formula in a function that I make.
>
> I create an object named qvartemp. This object is OK, look the levels:
> > print(levels(qvartemp))
>
> [1] "baixomedio" "alto"
>
> Now I create a new object with a new formula:
> > new.form <- as.formula(gsub(qvar,"qvartemp",as.expression(mma$formula)))
>
> Look this new object:
> > print(new.form)
>
> Riqueza ~ Biomassa * qvartemp
>
> Now here is the problem, I try to update an existing model (mma) changing
> the formula by the new.form
>
> mmaa <- update(mma,new.form)
>
> But my function is aborted with this message:
>
> Error in eval(expr, envir, enclos) : object "qvartemp" not found
>
> If I create this object qvartemp in R section manually it my function work,
> because it get the object from my workspace (but it is usefull just for
> testing), but my function dont find this object qvartemp created inside the
> function.
>
> If I run all my function line by line without use the function it work, I
> think that is because in this case the object is created in my workspace.
> But when I run a function the object is created only in memory (not in my
> workspece) and in this case update dont find this object.
>
> Anybody can suggest any Idea to fix it? I necessary I send my function and
> a example.
>
> Thanks
> Ronaldo

Completing the problem,

if I use

> mmaa <- glm(new.form) 

instead update(mma,new.form) the function work perfectly, but using update I 
can generalise my function and I need this. The problem is with update 
function, It maybe get the object differently, but I dont find the problem.

Thanks
Ronaldo 
-- 
Positive, adj.:
	Mistaken at the top of one's voice.
		-- Ambrose Bierce, "The Devil's Dictionary"
--
> Prof. Ronaldo Reis Júnior
|  .''`. UNIMONTES/Depto. Biologia Geral/Lab. de Biologia Computacional
| : :'  : Campus Universitário Prof. Darcy Ribeiro, Vila Mauricéia
| `. `'` CP: 126, CEP: 39401-089, Montes Claros - MG - Brasil
|   `- Fone: (38) 3229-8187 | ronaldo.reis em unimontes.br | chrysopa em gmail.com
| http://www.ppgcb.unimontes.br/ | ICQ#: 5692561 | LinuxUser#: 205366