see ?prod
b On May 7, 2007, at 2:25 PM, Jose Quesada wrote: > Hi, > > I need to multiply all columns in a matrix so something like > apply(x,2,sum), but using multiplication should do. > I have tried apply(x,2,"*") > I know this must be trivial, but I get: > Error in FUN(newX[, i], ...) : invalid unary operator > > The help for apply states that unary operators must be quoted. I tried > single quotes too, with the same results. > > Thanks, > -Jose > > -- > Jose Quesada, PhD. > http://www.andrew.cmu.edu/~jquesada > > ______________________________________________ > R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.