Use the tapply() function as in tapply(b,m,sum) HTH, Daniel
Don't "b" and "m" have to be the same length then? What if they're not? And would I just put the tapply() instead of everything else in my summing function? (Sorry! I'm kind of newbie at this -_-;) -- View this message in context: http://r.789695.n4.nabble.com/Summation-resulting-in-a-list-tp3660514p3660642.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.
