MATLAB: Using find to compare matrices

findunique

Hi
I have a matrix where the first column contains id's and the second some sort of information about thes id's, as an example such as below. What I want to do now, is to be able to say which information belongs to which id, for instance, for the example below, the id 1 has the "values" 5 and 9. So I would like to write code such that I could return for each id it's values. Now I have written that:
Y = [1,2,3,3,1; 5,6,7,8,9]'
 U = unique(Y(:,1)) 
for i= 1:length(U) 
  [A B] =  find(U(i)==Y(:,1)) 
end
Where the column with the 1,2,3,3,1 is storing these id's. Does that make any sense? What do I actually get returned in the [A B]?
Thanks a lot

Best Answer

You do not need find
Y = [1,2,3,3,1; 5,6,7,8,9]'
Y((Y(:,1)==1),2)   % id =1
Y((Y(:,1)==2),2)   % id=2
Y((Y(:,1)==3),2)   % id=3
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