Hi Kate, You could try
sum(X[, 1] == 1 & X[, 2] == 1) where X is your data set. HTH, Jorge.- On Sun, Jun 22, 2014 at 12:57 AM, Kate Ignatius <kate.ignat...@gmail.com> wrote: > I have 4 columns, and about 300K plus rows with 0s and 1s. > > I'm trying to count how many rows satisfy a certain criteria... for > instance, how many rows are there that have the first column == 1 as > well as the second column == 1. > > I've tried using rowSums and colSums but it keeps giving me this type of > error: > > Error in rowSums(X[1] == 1 & X[2] == 1) : > 'x' must be an array of at least two dimensions > > Thanks in advance! > > ______________________________________________ > 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. > [[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.
