MATLAB: Swap 3 random elements in an array

arraysexchangeMATLABmatrixpermutationswapvector

How do I randomly swap three elements in an array? The element at selected position one will be moved to selected position two, the previous element at selected position two will be moved to position three, and the element at position three will be moved to selected position one.

For example: a=[4 2 3 1 5 7 6] would become anew=[4 2 6 1 3 7 5]

Thank you

Best Answer

Use randperm to select 3 elements (without replacement) from your vector.

a = [4 2 3 1 5 7 6]
ind = randperm(numel(a), 3)
a(ind) = a(ind([3 1 2]))

Related Solutions

MATLAB: Find missing element between two matrix

>> A = [1,2;3,6;3,5;1,4;4,6;2,7;1,6;6,5;2,3;6,7;3,4];
>> B = [1,2;1,6;2,3;3,4;4,6];
>> R = setdiff(A,B,'rows')
R =
   1   4
   2   7
   3   5
   3   6
   6   5
   6   7

To get the same order, use the 'stable' option or this:

>> [~,X] = setdiff(A,B,'rows');
>> X = sort(X);
>> R = A(X,:)
R =
   3   6
   3   5
   1   4
   2   7
   6   5
   6   7

MATLAB: Dynamically arrange the matrix in each for loop

Definitely possible.

a = [3 5 6 7]; 
b = [2 4 6 1; 5 7 8 9];
for ii = 1:4
    % do_stuff(a,b);
      disp('iteration:')
      disp(ii);
      a
      b
      a = [a(end) a(1:end-1)];
      b = [b(:,end) b(:,1:end-1)];
end

Best Answer

Related Solutions

MATLAB: Find missing element between two matrix

MATLAB: Dynamically arrange the matrix in each for loop

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