member/2

Module: builtins

member/2 — list membership
dmember/2 — list membership

FORMS

member(Element, List)

dmember(Element, List)

DESCRIPTION

member/2 succeeds when Element can be unified with one of the elements in List. dmember/2 is the determinate version of member/2.

EXAMPLES

?- member(b, [a,b,c]).

yes.

?- member(foo, [bar | T]).

T=[foo|_A] 

yes.

?- member(X,[1,2,3]).

X=1;

X=2;

X=3;

no.

?- dmember(X,[1,2,3]).

X=1;

no.

NOTES

member/2 and dmember/2 are defined by the following clauses :

member(Item, [Item | _ ]) .

member(Item, [_ | Rest ]) :- member(Item, Rest) .

dmember(Item, [Item | _ ]) :- !.

dmember(Item, [_ | Rest ]) :- dmember(Item, Rest) .