non-consing count
Hi Sam, Here is one alternative, which is at least faster: system.time(count.0 <- length(which(x == 0))) system.time(count.1 <- sum(x == 0)) all.equal(count.0, count.1) Best, Ista
On Fri, Jan 4, 2013 at 10:30 AM, Sam Steingold <sds at gnu.org> wrote:
Hi, to count vector elements with some property, the standard idiom seems to be length(which): --8<---------------cut here---------------start------------->8--- x <- c(1,1,0,0,0) count.0 <- length(which(x == 0)) --8<---------------cut here---------------end--------------->8--- however, this approach allocates and discards 2 vectors: a logical vector of length=length(x) and an integer vector in which. is there a cheaper alternative? Thanks! -- Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000 http://www.childpsy.net/ http://iris.org.il http://honestreporting.com http://jihadwatch.org http://pmw.org.il http://www.PetitionOnline.com/tap12009/ War doesn't determine who's right, just who's left.
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