[R] lm() of one matrix against another

[baptiste Auguié]

Thanks for both replies, here is the cleaner version,

>
> n<-5
> N<-10
>
> data.x<-matrix(1:(n*N),ncol=n)
> data.y<-matrix(1:(n*N) + rnorm(n*N,sd=1),ncol=n)
>
> matplot(data.x,data.y,t="p",pch=1:n,bty="n")
>
> mapply(function(x,y){res <- lm(y~x) ; lines(x,predict(res)) ; res} ,
> 		as.data.frame(data.x),as.data.frame(data.y),SIMPLIFY=F)



Out of curiosity, I'm not sure if one could get the lines colored  
corresponding to their index within mapply (or any function of the  
apply family for that matter). Is there a special trick to refer to  
the index under evaluation?

Thanks again,

baptiste



On 12 Apr 2008, at 20:08, Henrique Dallazuanna wrote:
> Try
> mapply(function(x,y)lm(y~x),as.data
> .frame(data.x),as.data.frame(data.y),SIMPLIFY=F)
>
> 2008/4/12, baptiste Auguié <ba208 at exeter.ac.uk>:
>> Hello R list,
>>
>>
>> I have two matrices of identical dimensions, and I want to fit a
>> straight line for each pair of columns and plot the resulting lines.
>> I got it to work with a for loop, but there must be a better way,
>>
>>
>>> n<-5
>>> N<-10
>>>
>>> data.x<-matrix(1:(n*N),ncol=n)
>>> data.y<-matrix(1:(n*N) + rnorm(n*N,sd=1),ncol=n)
>>>
>>> matplot(data.x,data.y,t="p",pch=1:n,bty="n")
>>>
>>> for (ii in 1:n)
>>> {
>>> test <- lm(y~x,data=list(x=data.x[,ii],y=data.y[,ii]) )
>>> lines(data.x[,ii],test$coefficients[1] + test$coefficients[2] *
>>> data.x[,ii],lty=2,col=ii)
>>> }
>>
>>
>>
>> Thanks,
>>
>> baptiste
>>
>>
>> _____________________________
>>
>> Baptiste Auguié
>>
>> Physics Department
>> University of Exeter
>> Stocker Road,
>> Exeter, Devon,
>> EX4 4QL, UK
>>
>> Phone: +44 1392 264187
>>
>> http://newton.ex.ac.uk/research/emag
>> http://projects.ex.ac.uk/atto
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting- 
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O

_____________________________

Baptiste Auguié

Physics Department
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag
http://projects.ex.ac.uk/atto