You can try this also:
Reduce('+', lapply(mymats, function(x)replace(x, is.na(x), 0)))
On Sun, Sep 12, 2010 at 10:36 PM, Gregory Ryslik <rsa...@comcast.net> wrote:
> Hi Everyone,
>
> Thanks to everyone for their help. With your suggestions and some poking
> around, the following works for what I need. It basically adds all the
> matrices elementwise, and adds nothing if the element is NA. Thanks again!
> Code below:
>
>
> ******************************
> mymats <- vector('list', 5)
> set.seed(246)
>
> # Generate a list of five 3 x 3 matrices
> for(i in 1:5) mymats[[i]] <- matrix(sample(1:9), nrow = 3)
>
> mymats[[5]][1,1]<-NA
> mymats[[4]][2,2]<-NA
> mymats
>
> matrixadder<-function(u,v){
> na.u<-is.na(u)
> na.v<-is.na(v)
> ifelse(na.u & na.v, NA, ifelse(na.u, 0, u)+ ifelse(na.v,0,v))
> }
>
> Reduce('matrixadder',mymats)
> ******************************
>
> Cheers,
> Greg
>
>
>
>
> On Sep 12, 2010, at 8:33 PM, Ben Bolker wrote:
>
> > My next suggestion (I don't have time to work out or test an example
> > at the moment):
> >
> > library(abind)
> > tmparr <- abind(m1,m2,m3,...,along=3)
> > OR
> > tmparr <- do.call(c(matlist,list(along=3)))
> > apply(tmparr,c(1,2),mean,na.rm=TRUE)
> >
> > or something along those lines.
> >
> > ______________________________________________
> > 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.
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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