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_bo...@hotmail.com
To: michael.weyla...@gmail.com
Date: Tue, 18 Sep 2012 15:06:18 +0000
CC: r-help@r-project.org
Subject: Re: [R] extracting column and regular interval in R
thnkyou very much micheal.
i worked!!!
regards
eliza
From: michael.weyla...@gmail.com
Date: Tue, 18 Sep 2012 15:58:31 +0100
Subject: Re: [R] extracting column and regular interval in R
To: eliza_bo...@hotmail.com
CC: r-help@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_bo...@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
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______________________________________________
R-help@r-project.org mailing list
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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.
