Re: [R] get top 50 correlated item from a correlation matrix for each item

a possible vectorized solution is the following: cor.mat <- cor(matrix(rnorm(100*1000), 1000, 100)) p <- 30 # how many top items n <- ncol(cor.mat) cmat <- col(cor.mat) ind <- order(-cmat, cor.mat, decreasing = TRUE) - (n * cmat - n) dim(ind) <- dim(cor.mat) ind <- ind[seq(2, p + 1), ] out <- cb

Re: [R] get top 50 correlated item from a correlation matrix for each item

Works like a charm, thank you! -Original Message- From: Dimitris Rizopoulos [mailto:d.rizopou...@erasmusmc.nl] Sent: Thursday, February 12, 2009 12:11 PM To: Tan, Richard Cc: r-help@r-project.org Subject: Re: [R] get top 50 correlated item from a correlation matrix for each item a

Re: [R] get top 50 correlated item from a correlation matrix for each item

A solution using a toy example r <- cor(mvrnorm(1000,mu=rep(0,10),Sigma=diag(10))) #assume a 10 x 10 matrix j <- i<-1:dim(r)[1] #generate matrix indices lt <- outer(i,j,'>') #get boolean lower triangle sort(r[lt],decreasing=TRUE)[1:5] #extract top 5 correlations Joseph F. Lucke Senior Statis