try this:
> nom.plac2 <- c("102", "103", "301", "303","304", "403")
> poids2 <- matrix(NA, 6,6, dimnames=list(nom.plac2,nom.plac2))
> poids2
102 103 301 303 304 403
102 NA NA NA NA NA NA
103 NA NA NA NA NA NA
301 NA NA NA NA NA NA
303 NA NA NA NA NA NA
304 NA NA NA NA NA NA
403 NA NA NA NA NA NA
> wei2 <-
> matrix(c(.6,.4,.5,.5,.9,.1,.8,.2,.7,.3,.6,.4),6,2,dimnames=list(nom.plac2,
> c("p1","p2")),byrow=T)
> voisin <- matrix(c("103","304", "303", "102", "103"
> ,"303","403","304","303","102","103" ,"303"),
+ 6,2,dimnames=list(nom.plac2, c("v1","v2")),byrow=T)
>
> # do matrix addressing by converting names to numbers
> indx <- rbind(
+ cbind(match(rownames(voisin), rownames(poids2))
+ , match(voisin[, 1], colnames(poids2))
+ )
+ , cbind(match(rownames(voisin), rownames(poids2))
+ , match(voisin[, 2], colnames(poids2))
+ )
+ )
> indx
[,1] [,2]
[1,] 1 2
[2,] 2 4
[3,] 3 2
[4,] 4 6
[5,] 5 4
[6,] 6 2
[7,] 1 5
[8,] 2 1
[9,] 3 4
[10,] 4 5
[11,] 5 1
[12,] 6 4
>
> # change the data
> poids2[indx] <- c(wei2[,1], wei2[,2])
> poids2
102 103 301 303 304 403
102 NA 0.6 NA NA 0.4 NA
103 0.5 NA NA 0.5 NA NA
301 NA 0.9 NA 0.1 NA NA
303 NA NA NA NA 0.2 0.8
304 0.3 NA NA 0.7 NA NA
403 NA 0.6 NA 0.4 NA NA
>
>
>
On Thu, Nov 3, 2011 at 1:25 PM,
<[email protected]> wrote:
> Dear R community,
>
> I'm trying to remove a loop from my code but I'm stock and I can't find a
> good way to do it. Hopefully one of you will have something clever to
> propose.
>
> Here is a simplified example:
>
> I have a squared matrix:
>
>> nom.plac2 <- c("102", "103", "301", "303","304", "403")
>> poids2 <- matrix(NA, 6,6, dimnames=list(nom.plac2,nom.plac2))
>> poids2
> 102 103 301 303 304 403
> 102 NA NA NA NA NA NA
> 103 NA NA NA NA NA NA
> 301 NA NA NA NA NA NA
> 303 NA NA NA NA NA NA
> 304 NA NA NA NA NA NA
> 403 NA NA NA NA NA NA
>
> I want to replace some of the NAs following specific criterion included in 2
> others matrix:
>
>> wei2 <-
>> matrix(c(.6,.4,.5,.5,.9,.1,.8,.2,.7,.3,.6,.4),6,2,dimnames=list(nom.plac2,
>> c("p1","p2")),byrow=T)
>> wei2
> p1 p2
> 102 0.6 0.4
> 103 0.5 0.5
> 301 0.9 0.1
> 303 0.8 0.2
> 304 0.7 0.3
> 403 0.6 0.4
>> voisin <- matrix(c("103","304", "303", "102", "103"
>> ,"303","403","304","303","102","103" ,"303"),
> 6,2,dimnames=list(nom.plac2, c("v1","v2")),byrow=T)
>> voisin
> v1 v2
> 102 "103" "304"
> 103 "303" "102"
> 301 "103" "303"
> 303 "403" "304"
> 304 "303" "102"
> 403 "103" "303"
>
> So my final result is:
>
> 102 103 301 303 304 403
> 102 NA 0.6 NA NA 0.4 NA
> 103 0.5 NA NA 0.5 NA NA
> 301 NA 0.9 NA 0.1 NA NA
> 303 NA NA NA NA 0.2 0.8
> 304 0.3 NA NA 0.7 NA NA
> 403 NA 0.6 NA 0.4 NA NA
>
>
> So, globally I want to fill for each line of "poids2" data from "wei2"
> associated with the good the good identifier found in "voisin".
>
> This can easily be done by a loop:
>
>> loop <- poids2
>> for(i in 1:6){
> + loop[i,voisin[i,]] <- wei2[i,]
> + }
>
> But I expect it to be quite slow with my larger dataset.
>
> Does any of you has an idea how I could remove the loop and speed up the
> operation?
>
> Best regards,
>
>
> Bastien Ferland-Raymond, M.Sc. Stat., M.Sc. Biol.
> Division des orientations et projets spéciaux
> Direction des inventaires forestiers
> Ministère des Ressources naturelles et de la Faune du Québec
>
> ______________________________________________
> [email protected] 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.
>
--
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
