How to merge lists in PROLOG?

Question

I need to merge two lists L1=[1,2,3] and L2=[a,b] like this: M=[1,a,2,b,3]. How can I do it in PROLOG please?

Answer 1

you can try

m2([A|As], [B|Bs], [A,B|Rs]) :-
    !, m2(As, Bs, Rs).
m2([], Bs, Bs) :- !.
m2(As, [], As).