From: Marc Schwartz <MSchwartz_at_medanalytics.com>

Date: Thu 17 Mar 2005 - 04:07:48 EST

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 Received on Thu Mar 17 04:22:01 2005

Date: Thu 17 Mar 2005 - 04:07:48 EST

John,

Thanks for pointing that out. I see that Adai had a similar idea.

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: r-help-bounces@stat.math.ethz.ch
**> > [mailto:r-help-bounces@stat.math.ethz.ch] 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
**> >
**> > ______________________________________________
**> > 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
*

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 Received on Thu Mar 17 04:22:01 2005

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