[R] Average row and column

[David Winsemius]

On Mar 15, 2012, at 10:23 AM, MSousa wrote:

> Sorry, I ll explain better.
>
>    For example in the next dataset,
>
> x<-data.frame(v_source=3,v_destine=3,dist=4)
> x<-rbind(x,data.frame(v_source=7,v_destine=7,dist=0))
> x<-rbind(x,data.frame(v_source=6,v_destine=6,dist=0))
> x<-rbind(x,data.frame(v_source=4,v_destine=4,dist=56))
> x<-rbind(x,data.frame(v_source=4,v_destine=3,dist=61))
> x<-rbind(x,data.frame(v_source=3,v_destine=3,dist=300))
> x<-rbind(x,data.frame(v_source=3,v_destine=3,dist=27))
> x<-rbind(x,data.frame(v_source=3,v_destine=3,dist=87))
> x<-rbind(x,data.frame(v_source=3,v_destine=4,dist=49))
>
>
> when execute this instruction gives
> res<-table(x$v_source,x$v_destine)
>  3 4 6 7
> 3 4 1 0 0
> 4 1 1 0 0
> 6 0 0 1 0
> 7 0 0 0 1
>
> my idea is that if possible, is an array like this,  but instead of  
> having
> the frequency, appears the minimum or average. Appears 4 times,  
> instead of
> the value displayed in the matrix 4, show the average values. In the  
> case
> mean 104.5  average(4, 300,27,87).
>
>
> The idea was to the average value for each combination of row and  
> column.
> the idea is to get something like the following matrix.
>
>  3      4  6 7
> 3 104.5 49  0 0
> 4  61   56  0 0
> 6  0    0   1 0
> 7  0    0   0 1

Oh, then you want 'tapply':

 > tapply(x$dist, list(x$v_source, x$v_destine), mean)
       3  4  6  7
3 104.5 49 NA NA
4  61.0 56 NA NA
6    NA NA  0 NA
7    NA NA NA  0


>
>
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David Winsemius, MD
West Hartford, CT