if statement with loop in Mathlab

i want to make a IF statement with loop in Mathlab,

So i have a Range in X & Y and i have a domain thats i dont to calcualte the values of noeds in it,

for example : X[1:20] & Y[1:20]

and i want to ignore noeds of this range : X[5:7] & Y[12:14]

i think the code should be like this :

For X=1:20
For Y=1:20
If X=1:20 & Y=12:14
return
end
% the operation here !
T(X,Y) = lab lab lab
end
end