MATLAB: Suppose a row vector x=1:8 and another vector of same size z=[1 1 0 1 1 0 1 1].I want to swap element in x according to element in z if z==1 then swap the postion of element of x else z==0 element of x should be in same position in vector.

Question

The number of swap should be equal to number of one in vector z divide by 2 if even ones else plus one divide by 2.The value of z change after each iteration so logic should be universal.

Answer 1

Guessing that you want to swap the elements randomly:

x = rand(1, 8);  % Test data
z = [1 1 0 1 1 0 1 1];
xf   = x(z == 1);
n    = sum(z);          % Or: numel(xf)
p    = randperm(n, n);  % Faster than randperm(n)
x(z) = xf(p);

This does not guarantee, that the elements at z==1 are changed. If you need this, try: FEX: Shuffle:

p = Shuffle(n, 'derange', n)

Or if you have installed Shuffle already:

x(z==1) = Shuffle(x(z==1));