We will only be able to help if you provide a reproducible example! I'm sure this is a simple one-liner, but it's hard to tell from your example what it should be. The functions table, length, tapply, and/or nrow may play a part though.
-----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Dax Sent: Thursday, August 13, 2009 9:11 AM To: r-help@r-project.org Subject: [R] How to get the n (number of observations) per conditional group Hello all, I have a huge data set that I'm cleaning up a bit. I am extracted the means per condition, but also need to get the n. Strangely enough I am unable to find a function that could actually pull this off. I am unable to use replications or count the rows using nrow. What I am trying to obtain is the number of observations fitting something along the lines of "data$total[data$spp==1&data$gyro==1&data $salinity==0&data$day==i]" Can anyone help me? ______________________________________________ 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.
