Python nested loops with if statements unexpected result

I am trying to figure out why this code performs differently from how I would expect. The code is:

for i1 in [xrange(567)]:
    W = x1[i1]
    Z = y[i1]
    ZW = np.array([z * (1/w) for z, w in zip(Z,W)])
    for j1 in [xrange(567)]:
        if j1 != i1:
            E1 = np.array([z - zw * w for z, zw, w in zip(Z,ZW,W)])

Where x1 is a (566,1)-array and y a (566,2)-array from a .csv file. Now I think that the statement $if j1 != i1:$ doesn't work as it would be expected since if I try the more simple pattern:

for i in [range(567)]:
    for j in [range(567)]:
        if i != j:
            print i
            print j

It returns none