If all you want is a count, then you can construct a logical vector and count the TRUEs:
sum(a9 < (mean(a9) / 2)) On Sun, Apr 19, 2009 at 5:58 PM, Enda Hargaden <endaharga...@gmail.com> wrote: > Hi all, > > I've searched high and low on this and found nothing of help. I'm using > v2.6.2 and trying to write a function that will count how many people from a > dataset fall under a poverty line of 50% of the mean income. > > a9 is my 100-element vector of incomes. I want pa9 to be my vector that > counts how many of these are classed as in poverty. > > My problem is that my command if(a9[i] < mean(a9)/2 ) returns an "argument > is of length zero" error. But a9[i] is not really of length zero; if I > remove the if() command and simply set pa9[i] = a9[i] in the loop it comes > out fine. > > I don't think it's a problem with the type of variable either, because if I > multiply the vector by 2 I get the "correct" output, so I think it's a > problem with R interpreting my vector as a list of strings or anything. > > povertyline = function() > { > pa9 = c() > i=0 > while(i<=length(a9)) > { > if(a9[i] < mean(a9)/2) > { > pa9[i] = a9[i] > } > i = i+1 > } > return(length(pa9)) > } > > Has anyone any ideas what's going wrong? (Just for clarification: yes, this > is for my homework. However I've already done the assignment in Excel and > I'm repeating it to improve my R'ing.) > > Thanks a lot, > Enda > > [[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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.