Hi, Forgot to add a line: sumNew1<-rowSums(sapply(mycombos2,function(x) values1[x])) names(sumNew1)<- row.names(mycombos2) ###### identical(sumNew1,sum1) #[1] TRUE
Just checked with vectors of length 25 set.seed(25) values1<-rnorm(25) values2<-rnorm(25) values3<-rnorm(25) mycombos<-expand.grid(1:25,1:25,1:25,1:25) mycombos1<- mycombos mycombos2<-mycombos1[rowSums(sapply(as.data.frame(combn(names(mycombos1),2),stringsAsFactors=FALSE),function(x) mycombos1[x[1]]!=mycombos1[x[2]]))==6,] system.time(sum1<- apply(mycombos,1,function(x) sum(values1[x]))) # user system elapsed # 1.684 0.000 1.688 system.time(sumNew1<-rowSums(sapply(mycombos2,function(x) values1[x]))) # user system elapsed # 0.561 0.024 0.585 A.K. ----- Original Message ----- From: arun <smartpink...@yahoo.com> To: Dimitri Liakhovitski <dimitri.liakhovit...@gmail.com> Cc: R help <r-help@r-project.org>; Jorge I Velez <jorgeivanve...@gmail.com> Sent: Tuesday, March 26, 2013 9:39 AM Subject: Re: [R] Faster way of summing values up based on expand.grid HI, You could also try this: set.seed(25) values1<-rnorm(10) values2<-rnorm(10) values3<-rnorm(10) mycombos<-expand.grid(1:10,1:10,1:10,1:10) mycombos1<- mycombos mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var2),] mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var3),] mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var4),] mycombos<-mycombos[!(mycombos$Var2 == mycombos$Var3),] mycombos<-mycombos[!(mycombos$Var2 == mycombos$Var4),] mycombos<-mycombos[!(mycombos$Var3 == mycombos$Var4),] dim(mycombos) #[1] 5040 4 #the above steps could be collapsed by: mycombos2<-mycombos1[rowSums(sapply(as.data.frame(combn(names(mycombos1),2),stringsAsFactors=FALSE),function(x) mycombos1[x[1]]!=mycombos1[x[2]]))==6,] dim(mycombos2) #[1] 5040 4 head(mycombos2) # Var1 Var2 Var3 Var4 #124 4 3 2 1 #125 5 3 2 1 #126 6 3 2 1 #127 7 3 2 1 #128 8 3 2 1 #129 9 3 2 1 identical(mycombos,mycombos2) #[1] TRUE sum1<- apply(mycombos,1,function(x) sum(values1[x])) #Jorge's method sumNew1<-rowSums(sapply(mycombos2,function(x) values1[x])) identical(sumNew1,sum1) #[1] TRUE system.time(sum1<- apply(mycombos,1,function(x) sum(values1[x]))) # user system elapsed # 0.024 0.000 0.026 system.time(sumNew1<-rowSums(sapply(mycombos2,function(x) values1[x]))) # user system elapsed # 0.012 0.000 0.010 system.time(sumNew2<-rowSums(sapply(mycombos2,function(x) values2[x]))) system.time(sumNew3<-rowSums(sapply(mycombos2,function(x) values3[x]))) cbind(sumNew1,sumNew2,sumNew3) A.K. ----- Original Message ----- From: Dimitri Liakhovitski <dimitri.liakhovit...@gmail.com> To: r-help <r-help@r-project.org> Cc: Sent: Monday, March 25, 2013 5:00 PM Subject: [R] Faster way of summing values up based on expand.grid Hello! # I have 3 vectors of values: values1<-rnorm(10) values2<-rnorm(10) values3<-rnorm(10) # In real life, all 3 vectors have a length of 25 # I create all possible combinations of 4 based on 10 elements: mycombos<-expand.grid(1:10,1:10,1:10,1:10) dim(mycombos) # Removing rows that contain pairs of identical values in any 2 of these columns: mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var2),] mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var3),] mycombos<-mycombos[!(mycombos$Var1 == mycombos$Var4),] mycombos<-mycombos[!(mycombos$Var2 == mycombos$Var3),] mycombos<-mycombos[!(mycombos$Var2 == mycombos$Var4),] mycombos<-mycombos[!(mycombos$Var3 == mycombos$Var4),] dim(mycombos) # I want to write sums of elements from values1, values2, and values 3 whose numbers are contained in each column of mycombos. Here is how I am going it now - using a loop: mycombos$sum1<-NA mycombos$sum2<-NA mycombos$sum3<-NA for(i in 1:nrow(mycombos)){ mycombos$sum1[i]<-values1[[mycombos[i,"Var1"]]] + values1[[mycombos[i,"Var2"]]] + values1[[mycombos[i,"Var3"]]] + values1[[mycombos[i,"Var4"]]] mycombos$sum2[i]<-values2[[mycombos[i,"Var1"]]] + values2[[mycombos[i,"Var2"]]] + values2[[mycombos[i,"Var3"]]] + values2[[mycombos[i,"Var4"]]] mycombos$sum3[i]<-values3[[mycombos[i,"Var1"]]] + values3[[mycombos[i,"Var2"]]] + values3[[mycombos[i,"Var3"]]] + values3[[mycombos[i,"Var4"]]] } head(mycombos);tail(mycombos) # It's going to take me forever with this loop. Is there a faster way of doing the dame thing? Thanks a lot! -- Dimitri Liakhovitski [[alternative HTML version deleted]] ______________________________________________ R-help@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. ______________________________________________ R-help@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.