[R] Ordering a matrix by row value in R2.15

[soon yi]

or this with Pete's example

orig[,order(orig[2,])]





Pete Brecknock wrote
> 
> fitz_ra wrote
>> I know this is posted a lot, I've been through about 40 messages reading
>> how to do this so let me apologize in advance because I can't get this
>> operation to work unlike the many examples shown.
>> 
>> I have a 2 row matrix 
>>> temp
>>        [,1]     [,2]     [,3]     [,4]     [,5]     [,6]     [,7]    
>> [,8]     [,9]    [,10]
>> [1,] 17.000 9.000000 26.00000  5.00000 23.00000 21.00000 19.00000
>> 17.00000 10.00000  63.0000
>> [2,] 15.554 7.793718 33.29079 15.53094 20.44825 14.34443 11.83552
>> 11.62997 10.16019 115.2602
>> 
>> I want to order the matrix using the second row in ascending order.  From
>> the many examples (usually applied to columns) the typical solution
>> appears to be: 
>>> temp[order(temp[2,]),]
>> Error: subscript out of bounds
>> 
>> However as you can see I get an error here.
>> 
>> When I run this one line command:
>>> sort(temp[2,])
>>  [1]   7.793718  10.160190  11.629973  11.835520  14.344426  15.530939 
>> 15.553999  20.448249  33.290789
>> [10] 115.260192
>> 
>> This works but I want the matrix to update and the corresponding values
>> of row 1 to switch with the sort.
> Maybe consider the order function ....
> 
> orig <- matrix(c(10,20,30,3,1,2), nrow=2, byrow=TRUE)
> 
> new <-t(apply(orig,1,function(x) x[order(orig[2,])]))
> 
>> orig
>      [,1] [,2] [,3]
> [1,]   10   20   30
> [2,]    3    1    2
>> new
>      [,1] [,2] [,3]
> [1,]   20   30   10
> [2,]    1    2    3
> 
> HTH 
> 
> Pete





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