sort vs sortrows in Matlab
Is it possible to achieve the same functionality with sort function than using sortrows. My matrix has over 4million+ rows and sortrows is bringing in a lot of latency because of iterations. (a vectorizated approach would be appreciated)
%Col1 -> date, Col2 -> id, Col3 -> ranking within each date-group (to help you debug)
data = [ ...
734614 5 3; 734615 6 5; 734622 1 1; 734615 1 1; 734615 4 3;
734622 2 2; 734622 4 3; 734615 3 2; 734615 5 4; 734614 3 2;
734614 1 1; 734622 8 4; 734622 9 5;] ;
sortedanswer =
734614 1 开发者_Go百科 1
734614 3 2
734614 5 3
734615 1 1
734615 3 2
734615 4 3
734615 5 4
734615 6 5
734622 1 1
734622 2 2
734622 4 3
734622 8 4
734622 9 5
Thanks!
You could do it as
[~,indx]=sort(data(:,1));
sortedanswer=data(indx,:)
sortedanswer =
734614 5 3
734614 3 2
734614 1 1
734615 6 5
734615 1 1
734615 4 3
734615 3 2
734615 5 4
734622 1 1
734622 2 2
734622 4 3
734622 8 4
734622 9 5
Note that it is sorted by the rows in the first column. The order of the rows is the same as that in the original data
, which is why you see 5 3
in the second and third columns in the first row in mine.
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