Dear Srinivas, Your data are likely in a data frame rather than a matrix (since the columns are heterogeneous), and name is a variable, not the row names of the data frame.
There are several ways to do what you want; one simple way, assuming that the data are in a data frame named Data, is by(Data[,2:5], Data$name, mean) If you want the result in the form of a matrix, then you could do aggregate(Data[,2:5], list(Data$name), mean) I hope this helps, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox -------------------------------- > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Srinivas Iyyer > Sent: Friday, April 14, 2006 11:58 PM > To: [email protected] > Subject: [R] matching identical row names > > dear group, > > i have a sample matrix > name v1 v2 v3 v4 > cat 10 11 12 15 > dog 3 12 10 14 > cat 9 12 12 15 > cat 5 12 10 11 > dog 12 113 123 31 > ... > > > since cat is repeated 3 times, I want a mean value for it. > Like wise for every element of the name column. > cat v1 = mean(c(10,9,5)) > cat v3 = mean(c(11,12,13)) > ..etc. > > name v1 v2 v3 v4 > cat 8 11.6 11.3 13.6 > dog 7.5 62.5 66.5 22.5 > > could any one help me in solving this mystery. thank you. > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
