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
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