[R] loop problem for extract coefficients

[Arien Lam]

Hi Alex,

On Sun, April 5, 2009 16:49, Alex Roy wrote:
> Dear R users,
>                       I have problem with extracting coefficients from a
> object. Here, X (predictor)and Y (response) are two matrix , I am
> regressing
> X ( dimensions 10 x 20) on each of columns of Y[,1] (10 x 1)  and want to
> store the coefficient values. I have performed a Elastic Net regression
> and
> I want to store the coeffcients in each iteration. I got an error message
> .
> I do not know where is the problem???? Please help me.
>
> Thanks
>
>
>
> *Code:*
>
> -------------------------------------------------------
> library(elasticnet)
> X<-matrix(rnorm(200),ncol=20)
> Y<-matrix(rnorm(200),ncol=20)
> loop <- 20
> size <- 20
> enres<-matrix(nrow = size, ncol = loop)
> fit<-matrix(nrow = size, ncol = loop)
> store<-matrix(nrow = size, ncol = loop)
> for(j in 1: 10)
> print (paste(j,"/200",sep=""))
> {
> enres<-enet(x=X,y=Y[,j],lambda=1,normalize=TRUE,intercept=TRUE)
> fit<-predict.enet(enres, X, type="coefficients")
> store[,j]<-fit$coefficients
> }
> ----------------------------------------------------

The problem is that only the print statement is inside the for loop. I
would suggest:

for(j in 1: 10)
{             # here the opening bracket
print (paste(j,"/200",sep=""))
              # and not here!
enres<-enet(x=X,y=Y[,j],lambda=1,normalize=TRUE,intercept=TRUE)
fit<-predict.enet(enres, X, type="coefficients")
store[,j]<-fit$coefficients
}


Hope this helps,
Arien


>
>> library(elasticnet)
> Loading required package: lars
>> X<-matrix(rnorm(200),ncol=20)
>> Y<-matrix(rnorm(200),ncol=20)
>>
>> loop <- 20
>> size <- 20
>>
>> enres<-matrix(nrow = size, ncol = loop)
>> fit<-matrix(nrow = size, ncol = loop)
>> store<-matrix(nrow = size, ncol = loop)
>>
>> for(j in 1: 10)
> + print (paste(j,"/200",sep=""))
> [1] "1/200"
> [1] "2/200"
> [1] "3/200"
> [1] "4/200"
> [1] "5/200"
> [1] "6/200"
> [1] "7/200"
> [1] "8/200"
> [1] "9/200"
> [1] "10/200"
>> {
> + enres<-enet(x=X,y=Y[,j],lambda=1,normalize=TRUE,intercept=TRUE)
> + fit<-predict.enet(enres, X, type="coefficients")
> + store[,j]<-fit$coefficients
> + }
> *Error in store[, j] <- fit$coefficients :
>   number of items to replace is not a multiple of replacement length
>> *
>
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>
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-- 
drs. H.A. (Arien) Lam (Ph.D. student)
Department of Physical Geography
Faculty of Geosciences
Utrecht University, The Netherlands