Or, if X1 Y1 X2 Y2... are really your column names
m[, grep("X",colnames(m)) ]
or
m[, grepl("X",colnames(m)) ]-----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Dimitris Rizopoulos Sent: Wednesday, March 09, 2011 9:36 AM To: Nixon, Matthew Cc: r-help@R-project.org Subject: Re: [R] Extracting only odd columns from a matrix one way is using the seq(), e.g., say 'm' is your matrix, then try: m[, seq(1, ncol(m), by = 2)] I hope it helps. Best, Dimitris On 3/9/2011 3:20 PM, Nixon, Matthew wrote: > Hi, > > This might seem like a simple question but at the moment I am stuck for > ideas. The columns of my matrix in which some data is stored are of this form: > > X1 Y1 X2 Y2 X3 Y3 ... Xn Yn > > with n~100. I would like to look at just the X values (i.e. odd column > numbers). Is there an easy way to loop round extracting only these columns? > > Any help would be appreciated. > > Thank you. > ______________________________________________ > 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. > -- Dimitris Rizopoulos Assistant Professor Department of Biostatistics Erasmus University Medical Center Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands Tel: +31/(0)10/7043478 Fax: +31/(0)10/7043014 Web: http://www.erasmusmc.nl/biostatistiek/ ______________________________________________ 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. message may contain confidential information. If you are not the designated recipient, please notify the sender immediately, and delete the original and any copies. Any use of the message by you is prohibited. ______________________________________________ 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.
