Use this function:
mode <- function(x, ...)
as.numeric(names(which.max(table(x, useNA = 'ifany'))))
On Tue, Sep 21, 2010 at 4:18 PM, Gregory Ryslik <rsa...@comcast.net> wrote:
> Hi,
>
> Much better! That seems to work great. The only time it doesn't work is
> that if all the elements are NA for a specific element. Then it gives me a
> numeric(0) for that cell rather than NA.
>
> On Sep 21, 2010, at 2:30 PM, Henrique Dallazuanna wrote:
>
> Try this:
>
> apply(array(unlist(mymats), dim = c(dim(mymats[[1]]), length(mymats))),
> 1:2, mode)
>
> The error was in c(length(mymats), dim(mymats[[1]]))
>
> On Tue, Sep 21, 2010 at 3:19 PM, Gregory Ryslik <rsa...@comcast.net>wrote:
>
>> Ack, apologies for the previous email. What I meant to say is that the
>> first element is calculated incorrectly (1,1) should be 2, instead it is 3.
>> I've been staring at the code for two long. I've copied it in again for
>> convenience.
>>
>> mymats <- vector('list', 4)
>> set.seed(246)
>>
>> # Generate a list of 4 3 x 3 matrices
>> 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
>>
>>
>>
>
>
> --
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>
>
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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