Right.
Michael Weylandt wrote > > I'd use a combination of rownames(), grepl() and sum(). > > Get the names with the first, test with the second and count the positives > (by coercing TRUE -> 1) with the last > > Michael > > On Apr 29, 2012, at 3:46 PM, katarv <katiasmirn@> wrote: > >> Hi, >> >> I have a large data set that I input as a matrix, where I have 1:x rows >> with names AX, then x+1: y rows named AY, etc. The idea is that I have >> to >> count how many rows exactly I have with name AX and how many I have with >> name AY (or find which row numbers have names AX). Is there any way in R >> to >> count a number of rows with a name matching a required pattern? >> >> >> Thanks in advance, >> >> Katie >> >> -- >> View this message in context: >> http://r.789695.n4.nabble.com/Count-number-of-rows-in-a-matrix-with-a-character-pattern-tp4596848p4596848.html >> Sent from the R help mailing list archive at Nabble.com. >> >> ______________________________________________ >> R-help@ 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@ 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. > Misread the op. Didn't see 'count', my code gives where, not how many. So the corrected version shoulld be sum(grepl("AY", rnames)) Rui Barradas -- View this message in context: http://r.789695.n4.nabble.com/Count-number-of-rows-in-a-matrix-with-a-character-pattern-tp4596848p4597035.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
