[R] predict.glm & newdata

[Yasir Kaheil]

You could just say:
yhat=predict(reg1,x2)
the function predict will assing x2 to 'newdata' by default.
thanks




Daniel Malter wrote:
> 
> Hi,
> 
> could it be the "newdata" argument? When I run predict with the newdata
> argument, I get an error message - a different one though. The second
> reason
> might be that your dataset is named df, which is defined as a function an
> may produce problems. Try renaming the dataset.
> 
> yhat=predict(reg1,newdata=x2) 
> 
> x1=seq(1:100)           
> r.norm1=rnorm(100,0,20) 
> x1=r.norm1+x1           
>                         
> x2=x1*2                 
> r.norm2=rnorm(200,0,20) 
> x2=r.norm2+x2
> 
> reg1=glm(y1~x1,binomial)      
> yhat=predict(reg1) 		     ##prediction works fine           
> yhat=predict(reg1,newdata=x2) ##gives error message because of "newdata"
> 
>>Error in eval(predvars, data, env) : 
>   numeric 'envir' arg not of length one
> 
> yhat=predict(reg1,data=x2) ##works fine
> 
> ##using offset
> 
> ofst=rep(0.5,100)                    
>                                      
> reg1=glm(y1~x1,binomial,offset=ofst) 
> yhat=predict(reg1)                   
> yhat1=predict(reg1,newdata=x2) ##gives error message       
> yhat2=predict(reg1,data=x2)      ##works fine               
> 
> 
> -------------------------
> cuncta stricte discussurus
> -------------------------
> 
> -----Ursprüngliche Nachricht-----
> Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im
> Auftrag von Tom Guston
> Gesendet: Friday, April 04, 2008 1:29 PM
> An: r-help at r-project.org
> Betreff: [R] predict.glm & newdata
> 
> 
> Hi all - 
> 
> I'm stumped by the following
> 
> mdl <- glm(resp ~ . , data = df, family=binomial, offset = ofst) WORKS
> yhat
> <- predict(mdl) WORKS yhat <- predict(mdl,newdata = df) FAILS
> 
> Error in drop(X[, piv, drop = FALSE] %*% beta[piv]) : 
>   subscript out of bounds
> 
> 
> I've tried without offset, quoting binomial. The offset variable ofst IS
> in
> df.
> 
> Previous postings indicate possible names(df) problems (renaming factor
> levels?) but I'm using the same data.frame for the newdata option.
> 
> Thank you in advance for any pointers.
> 
> Tom.
> 
> 
> 
> 
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