i have one dimensional array and i want to move every non zero element oh that array to exchange position with every zero in each iteration.

For example

a=[1 2 3 4 0 0 0 ]

I want all the possible combination through nested for loop (not circular shift)

example of Iterations are like

4 will replace its position with 0 (on the right)

a1=[1 2 3 0 4 0 0]

a2=[1 2 3 0 0 4 0]

a3=[1 2 3 0 0 0 4]

now 4 returns to its original position and 3 will shift its position with 0 (on right on 4) move left place one by one

a4=[1 2 0 4 3 0 0]

a5=[1 2 0 4 0 3 0]

a6=[1 2 0 4 0 0 3]

now 3 returns to its original position and 2 replaces its position with 0 (right of 4) move left place one by one

a7=[1 0 3 4 2 0 0 ]

a8=[1 0 3 4 0 2 0 ]

a9=[1 0 3 4 0 0 2 ]

now 2 reutrns to its original position and 1 replaces its position with 0

a10=[0 2 3 4 1 0 0]

a11=[0 2 3 4 0 1 0]

a12=[0 2 3 4 0 0 1]

[John D'Errico]

Are you sure this is what you want? It seems like you might want ALL ways of sorting the elements of the array, and this gives you only a subset of the permutations.

Answer 1

[the cyclist]

I think this does what you want:

% Input data
a = [1 2 3 4 0 0 0];

% Find the indices of the non-zeros and the zeros
idxNotZero = find(a~=0);
idxZero = find(a==0);

% Preallocate the array c that holds the output
numberCombos = numel(idxNotZero).*numel(idxZero);
c = zeros(numberCombos,numel(a));

% For all pairs of zero and non-zero elements, write a new row that swaps
% them
nr = 0;
for inz = idxNotZero
for iz = idxZero
    nr = nr + 1;
    c(nr,:) = swapIt(a,inz,iz);
end
end

c

c = 12×7

0 2 3 4 1 0 0 0 2 3 4 0 1 0 0 2 3 4 0 0 1 1 0 3 4 2 0 0 1 0 3 4 0 2 0 1 0 3 4 0 0 2 1 2 0 4 3 0 0 1 2 0 4 0 3 0 1 2 0 4 0 0 3 1 2 3 0 4 0 0

% Function that swaps two elements of a vector, given the element indices
function [out] = swapIt(a,i,j)
    out = a;
    out([i j]) = out([j i]);
end