[R] sort a matrix on just one column

Petr Pikal petr.pikal at precheza.cz
Wed Sep 10 17:11:18 CEST 2003


Hi

On 10 Sep 2003 at 10:50, Paul Green wrote:

> How can I sort(decreasing) a matrix on just the first column?
> For example, I can I get
> 
>    8  2
>    7  5
>    4  1
> 
> from
> 
>    7  5
>    4  1
>    8  2

I am sure in help pages for sort() is a link to order()

> mat
     x y
[1,] 7 5
[2,] 4 1
[3,] 8 2

> o<-order(mat[,1],decreasing=T)

> mat[o,]
     x y
[1,] 8 2
[2,] 7 5
[3,] 4 1


> 
> Thanks
> 
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CheersPetr Pikal
petr.pikal at precheza.cz




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