> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Murat Tasan > Sent: Sunday, September 27, 2009 4:27 PM > To: r-help@r-project.org > Subject: Re: [R] Count number of zeros in a collumn > > more generally, if you want to test for some minimum threshold T on > the number of zeros, try: > > > if(length(which(dart[,1977] == 0)) < T) { # some code to > handle the too-few-zeros-case }
Note that sum( dart[,1977]==0 ) gives the same result as length(which( dart[,1977]==0 )) with less typing and using less memory and time. Arithmetic on logicals treats TRUE as 1 and FALSE as 0. (sum() forces you to decide what to do with NA's in the data; which() always discards them.) Bill Dunlap TIBCO Software Inc - Spotfire Division wdunlap tibco.com > > > > > On Sep 27, 4:54 pm, Marcio Resende <mresende...@yahoo.com.br> wrote: > > I have a matrix 700x2000 which is sampled in each cycle > from another matrix > > 788x2000 with the numbers 0,1 and 9 > > > > There is one specific collumn of this matrix, dart[,1977], > that usually, > > after the samplimg procedure has only 1 and 9 (because the > zero frequency in > > this collumn is low). > > However, when this happens, I want to include an IF > conditional in my code. > > so basically what i wanted to do was to count the number of > zeros in this > > collumn to use this information in my conditional: > > > > something like: > > > > if (the number of zeros in collumn [,1977] is zero) ... else ... > > > > I tried to find out indirectly by the rowsum but because of > the sampling > > procedure the rowsum is not always the same > > > > Thank you very much > > -- > > View this message in > context:http://www.nabble.com/Count-number-of-zeros-in-a-collu > mn-tp25637516p2... > > Sent from the R help mailing list archive at Nabble.com. > > > > ______________________________________________ > > r-h...@r-project.org mailing > listhttps://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting > guidehttp://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. > ______________________________________________ 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.
