Get all row indices where values of to columns reach their maximum
1 view (last 30 days)
Show older comments
Hey,
i would like to get an array containing the indices of all rows in which the values of column 2 and 3 reach their maximum at the same time.
Example:
A = [1 2 3;
1 4 3;
2 4 3;
1 4 2];
Output should be an array containing the values 2 and 3 corresponding to row 2 and 3 of array A since the values in column 2 and 3 both reach their maximum at the same time.
Output = [2 3];
Thank You :-)
0 Comments
Accepted Answer
Les Beckham
on 3 Feb 2023
A = [1 2 3;
1 4 3;
2 4 3;
1 4 2];
m = max(A(:,2:end), [], 1)
Output = find(all(ismember(A(:,2:end), m), 2))
4 Comments
Voss
on 4 Feb 2023
@Georg Bauer: What should Output be when A is as follows?
A = [1 2 3;
1 4 3;
2 3 3;
1 4 2];
% get column-wise maxima:
m = max(A(:,2:end), [], 1);
The given answer will give [2; 3] since rows 2 and 3 both have all values in their 2nd and 3rd columns as elements of the column-wise maxima m ([3 4]):
Output = find(all(ismember(A(:,2:end), m), 2))
But I think you want the result to be row 2 only, since that's the only row where the column-wise maxima occur in the same row, in which case you can use this logic, to compare elements in each column individually:
Output = find(all(A(:,2:end) == repmat(m,size(A,1),1), 2))
More Answers (0)
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!