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

Hi, I have a correlation matrix of about 3000 items, i.e., a 3000*3000 matrix. For each of the 3000 items, I want to get the top 50 items that have the highest correlation with it (excluding itself) and generate a data frame with 3 columns like ("ID", "ID2", "cor"), where ID is those 3000 items

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

Joseph F. Lucke Senior Statistician Research Institute on Addictions University at Buffalo SUNY "Tan, Richard" Sent by: r-help-boun...@r-project.org 02/12/2009 11:19 AM To cc Subject [R] get top 50 correlated item from a correlation matrix for each item Hi, I have a correlat