@vv 

restart;
phi := (p__1, p__2, p__3, p__4, q__1, q__2, q__3, q__4, xi) -> (p__1*exp(q__1*xi) - p__2*exp(q__2*xi))/(p__3*exp(q__3*xi) + p__4*exp(q__4*xi));
xi := x;
for p__1 in [1, -1, I, -I] do
    for p__2 in [1, -1, I, -I] do for p__3 in [1, -1, I, -I] do for p__4 in [1, -1, I, -I] do for q__1 in [1, -1, I, -I] do for q__2 in [1, -1, I, -I] do for q__3 in [1, -1, I, -I] do for q__4 in [1, -1, I, -I] do result1 := evalf(phi(p__1, p__2, p__3, p__4, q__1, q__2, q__3, q__4, xi)); print('phi'(p__1, p__2, p__3, p__4, q__1, q__2, q__3, q__4, xi) = result1); end do; end do; end do; end do; end do; end do; end do;
end do;

in one place stop and not continues when is zero how tell him not calculate that one which is equal to zero?

@vv  thank you so much ...

@mmcdara  i already use it but in first picture i crop the picture.

@Carl Love thanks a lot it is worked