分隔序言中的事实列表

Question

I have a list of facts in Prolog. Say:

L = [mother(sue), father(sam), mother(rachel), mother(izzie), father(leo)] 

I want to separate them into two lists

L1 = [mother(sue), mother(rachel), mother(izzie)]
L2 = [father(sam), father(leo)]

How do I do that in Prolog

Answer 1

I hope I'm not doing your homework for you, but here it is:

split([], [], []).
split([mother(X)|L], [mother(X)|L1], L2) :- split(L, L1, L2).
split([father(X)|L], L1, [father(X)|L2]) :- split(L, L1, L2).

Usage:

?- split([mother(sue), father(sam), mother(rachel), mother(izzie), father(leo)], L1, L2).
L1 = [mother(sue), mother(rachel), mother(izzie)],
L2 = [father(sam), father(leo)]