On Fri, 2010-02-26 at 10:43 -0800, David Reinke wrote: > The length will remain the same no matter what expression appears in > the subscript.
No it won't! x == 1 evaluates to logical and when used to *subset* x, it *will* return the required answer. As observed with this example: > set.seed(1) > x <- sample(rep(1:3, times = 20)) > x [1] 1 1 1 1 3 2 3 3 3 1 2 3 3 1 2 2 2 1 3 2 2 1 1 2 1 2 1 1 1 1 [31] 3 3 2 3 2 2 2 3 3 3 1 3 3 1 3 2 1 1 2 2 1 1 3 2 2 3 2 2 3 3 > > ## compare > sum(x == 1, na.rm = TRUE) [1] 20 > length(x) [1] 60 > length(x[x == 1]) [1] 20 G > I suggest this: > > sum(x == 1) > > David Reinke > > Senior Transportation Engineer/Economist > Dowling Associates, Inc. > 180 Grand Avenue, Suite 250 > Oakland, California 94612-3774 > 510.839.1742 x104 (voice) > 510.839.0871 (fax) > www.dowlinginc.com > > Please consider the environment before printing this e-mail. > > Confidentiality Notice: This e-mail message, including any attachments, is > for the sole use of the intended recipient(s), and may contain confidential > and privileged information. Any unauthorized review, use, disclosure or > distribution is prohibited. If you are not the intended recipient, please > contact the sender by reply e-mail and destroy all copies of the original > message. > > > > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Randall Wrong > Sent: Friday, February 26, 2010 6:44 AM > To: r-help@r-project.org > Subject: [R] counting the number of ones in a vector > > Dear R users, > > I want to count the number of ones in a vector x. > > That's what I did : length( x[x==1] ) > > Is that a good solution ? > > Thank you very much, > Randall > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > > ______________________________________________ > 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. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ 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.
