> -----Original Message----- > When I try to apply mean to a list, I get the answer : > > argument is not numeric or logical: returning NA > Example: l4 <- list(1:4) class(l4) #not numeric or logical ... mean(l4) #same error
#a list is not a number, a logical (TRUE/FALSE) or a vector or array of either of those. So mean() can't handle it unaided and tells you what it needs. #But if your list is a list of numeric objects, unlist will often work. unlist(l4) #a numeric vector mean( unlist(l4) ) #no problem l.some <- list(matrix(1:4, ncol=2), 3:7) l.some unlist(l.some) #a numeric vector mean( unlist(l.some) ) #works #But a) magic has limits and b) if you want averages, maybe you should not be using a list? A vector would save hassle if it fits ... S Ellison ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}} ______________________________________________ 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.