Help: sort a m by n matrix

Hi,

I have a 4 by 2 matrix. c=[2205 300; 7281 300; 3535 600; 5944 600] and want to sort the 1st colum and the 2nd colum by the 1st one. The result I want to obtain is a 4 by 2 matrix like this c'= [2205 300; 3535 600; 5944 600; 7281 300].

I also wrote a script to do it. For convenience, is there a buit-in function MATLAB to do it?

My script:

for i=1:size(c,1)
    if i<size(c,1)
    if c(i,1)>c(i+1,1)
        xiold=c(i,1)
        xi1old=c(i+1,1)
        yiold=c(i,2)
        yi1old=c(i+1,2)
        c(i,1)=xi1old
        c(i+1,1)=xiold
        c(i,2)=yi1old
        c(i+1,2)=yiold

      end
      end
  end

Khanh

Answer 1

[Hikaru]

Yes, there is a built-in function.

c1 = sortrows(c,1)

[Roger Stafford]

That would leave the second column unsorted. It should either be

   c1 = sortrows(c);

or

   c1 = sortrows(c,[1,2]);

[Khanh]

Thanks all.