extracting column at regular intervals starting from different columns
Try: x <- 1:444 start<-2
x[c(rep(FALSE,start-1),TRUE, rep(FALSE, 36-start+1))]
# [1] 2 39 76 113 150 187 224 261 298 335 372 409
start<-30
x[c(rep(FALSE,start-1),TRUE, rep(FALSE, 36-start+1))]
# [1] 30 67 104 141 178 215 252 289 326 363 400 437
start<-37
x[c(rep(FALSE,start-1),TRUE, rep(FALSE, 36-start+1))]
# [1] 37 74 111 148 185 222 259 296 333 370 407 444
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On Tue, 18 Sep 2012, eliza botto wrote:
Dear useRs, i had a matrix with 31 rows and 444 columns and i wanted to extract every 37th column of that matrix starting from 1. more precisely i wanted to select columns 1, 38,75, 112 and so on. then doing the same by starting from column number 2(2,39,76,113.......). i was advised to use
x[c(TRUE, rep(FALSE, 36)),]
i works if it is start from first column but as i am very new to R i wanted to know what to do to make it work if i want to start column selection from column 2 and then from column 3 and so on. sorry for bothering you once again.. regards eliza
From: eliza_botto at hotmail.com To: michael.weylandt at gmail.com Date: Tue, 18 Sep 2012 15:06:18 +0000 CC: r-help at r-project.org Subject: Re: [R] extracting column and regular interval in R thnkyou very much micheal. i worked!!! regards eliza
From: michael.weylandt at gmail.com Date: Tue, 18 Sep 2012 15:58:31 +0100 Subject: Re: [R] extracting column and regular interval in R To: eliza_botto at hotmail.com CC: r-help at r-project.org x[c(TRUE, rep(FALSE, 36)),] and let recycling work its magic! To concretize: x <- 1:100 x[c(TRUE, rep(FALSE, 4))] Cheers, Michael On Tue, Sep 18, 2012 at 3:55 PM, eliza botto <eliza_botto at hotmail.com> wrote:
Dear R users, i have a matrix with 31 rows and 444 columns and i want to extract every 37th column of that matrix starting from 1. more precisely i want to select columns 1, 38,75, 112 and so on. then doing the same by starting from column number 2(2,39,76,113.......). i know that there is a manual way of doing it but i wanted to make it more quickly as i have fairly large data to dealth with. thanks in advance eliza [[alternative HTML version deleted]]
______________________________________________ R-help at 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.
[[alternative HTML version deleted]]
______________________________________________ R-help at 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.
[[alternative HTML version deleted]]
______________________________________________ R-help at 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.