Arrange points by y cordinate within a stucture array

Would anyone know a way of arranging a structure arrays points by y cordinate indescending order? I dont even know how to go about starting this. Any help would be appreciated.

For example i have a structure with each field being an element, each element has a cordinate [x,y,z] and id like to order this coulmn of points by the y cordinate.

ive tried using a nested for loop to acheive this to start parcing through the structure, but am not capturing all of the fields in the structure. OutputTable is the structure.

    for iRun = 1:1:length(outputTable)
        
        for iObj = 1:1:length(outputTable(iRun).tubingRuns.objects)
        
            objectTable = sort([outputTable.tubingRuns(iRun).objects(iObj).centroid(2)]);
            sortTable(iRun).tubingRuns.objects(nextIndex).centroid = objectTable;
        
        end
        
    end
    

Answer 1

[Ameer Hamza]

Try something like this

% example struct array 's'.
s(1).coordinate = [1 4 3];  s(1).id = 1;
s(2).coordinate = [8 0 7];  s(2).id = 2;
s(3).coordinate = [5 6 12]; s(3).id = 3;

x = vertcat(s.coordinate);
[~, idx] = sort(x(:,2));
s = s(idx);

elements of 's' are sorted according to second column of 'coordinate'.

[Ikenna Okoye]

Thanks for answering. What is 'idx' supposed to represent?

[Ameer Hamza]

It is a variable name, and It is assigned the second output of sort(). The 2nd output of sort tells us the location of sorted elements in the original array.

[Ikenna Okoye]

I see, so in this case it would be the x,y or z position? Why is there a tilde (~) in the first position of the assignment on the left side of the code?

[Ameer Hamza]

The first output of sort is the sorted matrix itself. In this case, it will be the sorted values in the 2nd column of matrix x. However, it is of no interest, in this case, so we tell MATLAB (using ~) to discard the first output.

[Ikenna Okoye]

Thanks so much for explaining!

[Ameer Hamza]

I am glad to be of help.