Hi,
That doesn't work as seen in this example. I get a 4x3 matrix as the answer
which is definitely not right!
But I think we're getting closer!
Cheers,
G
for(i in 1:4) mymats[[i]] <- matrix(sample(1:9), nrow = 3)
mymats[[1]][1,1]<-3
mymats[[1]][1,2]<-3
mymats[[1]][1,3]<-1
mymats[[2]][2,1]<-2
mymats[[1]][2,2]<-3
mymats[[1]][2,3]<-1
mymats[[1]][3,1]<-2
mymats[[1]][3,2]<-2
mymats[[1]][3,3]<-3
mymats[[2]][1,1]<-2
mymats[[2]][1,2]<-3
mymats[[2]][1,3]<-2
mymats[[2]][2,1]<-1
mymats[[2]][2,2]<-2
mymats[[2]][2,3]<-2
mymats[[2]][3,1]<-1
mymats[[2]][3,2]<-3
mymats[[2]][3,3]<-2
mymats[[3]][1,1]<-NA
mymats[[3]][1,2]<-2
mymats[[3]][1,3]<-2
mymats[[3]][2,1]<-2
mymats[[3]][2,2]<-3
mymats[[3]][2,3]<-1
mymats[[3]][3,1]<-2
mymats[[3]][3,2]<-2
mymats[[3]][3,3]<-3
mymats[[4]][1,1]<-2
mymats[[4]][1,2]<-1
mymats[[4]][1,3]<-2
mymats[[4]][2,1]<-3
mymats[[4]][2,2]<-2
mymats[[4]][2,3]<-3
mymats[[4]][3,1]<-1
mymats[[4]][3,2]<-2
mymats[[4]][3,3]<-1
mymats
mode <- function(x){
as.numeric(names(which.max(table(x))))
}
apply(array(unlist(mymats), dim = c(length(mymats), dim(mymats[[1]]))), 1:2,
mode)
On Sep 21, 2010, at 10:08 AM, Henrique Dallazuanna wrote:
> Try this:
>
> mode <- function(x, ...)
> as.numeric(names(which.max(table(x))))
> apply(array(unlist(mymats), dim = c(length(mymats), dim(mymats[[1]]))), 1:2,
> mode)
>
>
> On Tue, Sep 21, 2010 at 10:47 AM, Gregory Ryslik <rsa...@comcast.net> wrote:
> Hi Everyone,
>
> I am interested in taking the mode over several thousand matrices. I show an
> example below. For the [1,1] entry of my "mode" matrix that I want to create
> I would like to have a "2". For the [1,2] entry I would want a 2. For the
> [2,2] entry it would be 4 and so forth. Earlier, I was working with
> continuous cases and thus each (n,m) element was simply an average. I was
> able to then do element-wise addition and counting using the "Reduce"
> function and then the average would be totalsum/totalcount where the NA terms
> were discounted. Here, it's not exactly a binary case so Reduce doesn't quite
> work as well. I'm open to suggestions but would as always like to avoid long
> loops as that will significantly bump up running time over several thousand
> trees. Similarly, I would not like to do a lot of sorts to find the mode
> either...
>
> Thanks for your help!
>
> mymats
> [[1]]
> [,1] [,2] [,3]
> [1,] 0 2 1
> [2,] 2 3 3
> [3,] 2 1 2
>
> [[2]]
> [,1] [,2] [,3]
> [1,] 1 2 4
> [2,] 2 4 4
> [3,] 3 4 5
>
> [[3]]
> [,1] [,2] [,3]
> [1,] 2 3 1
> [2,] 3 4 2
> [3,] 5 1 3
>
> [[4]]
> [,1] [,2] [,3]
> [1,] 2 4 2
> [2,] 1 NA 2
> [3,] 2 3 1
>
> [[5]]
> [,1] [,2] [,3]
> [1,] NA 2 1
> [2,] 2 4 1
> [3,] 1 3 2
> ______________________________________________
> 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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