John, That is correct. I took the example perhaps too literally, depending upon what Vicky requires. If indeed the data structure is comprised of >2 matrices, the approach using do.call() will not work.
Thanks for pointing that out. I see that Adai had a similar idea. Best regards, Marc On Wed, 2005-03-16 at 12:00 -0500, John Fox wrote: > Dear Mark, > > I believe that your solution won't work if there are more than two matrices > to sum. > > Regards, > 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 Marc Schwartz > > Sent: Wednesday, March 16, 2005 11:30 AM > > To: Vicky Landsman > > Cc: R-Help > > Subject: Re: [R] Summing up matrices in a list > > > > On Wed, 2005-03-16 at 18:21 +0200, Vicky Landsman wrote: > > > Dear all, > > > I think that my question is very simple but I failed to solve it. > > > I have a list which elements are matrices like this: > > > > > > >mylist > > > [[1]] > > > [,1] [,2] [,3] > > > [1,] 1 3 5 > > > [2,] 2 4 6 > > > > > > [[2]] > > > [,1] [,2] [,3] > > > [1,] 7 9 11 > > > [2,] 8 10 12 > > > > > > I'd like to create a matrix M<-mylist[[1]]+mylist[[2]] > > > [,1] [,2] [,3] > > > [1,] 8 12 16 > > > [2,] 10 14 18 > > > > > > Is there a way to create M without looping? > > > Thanks a lot, > > > > > > > do.call("+", mylist) > > [,1] [,2] [,3] > > [1,] 8 12 16 > > [2,] 10 14 18 > > > > See ?do.call for more information. > > > > HTH, > > > > Marc Schwartz > > > > ______________________________________________ > > [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
