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# nonmember(+Element, +List)

Succeeds if Element is not an element of the list List.

+Element
  Prolog term.
+List
  List.

## Description

Used to check that Element is not a member of the list List.

The definition of this Prolog library predicate is:

    nonmember(Arg,[Arg|_]) :-
            !,
            fail.
    nonmember(Arg,[_|Tail]) :-
            !,
            nonmember(Arg,Tail).
    nonmember(_,[]).

This predicate does not perform any type testing functions.

### Modes and Determinism

- nonmember(+, +) is semidet

### Fail Conditions

Fails if Element is an element of the list List.

### Resatisfiable

No.

## Examples

    Success:
      nonmember(q,[1,2,3,4,5,6,7]).

    Fail:
      nonmember(1,[1,2,3]).
      nonmember(q,[1,2,2,X]). % X and q are unifiable

## See Also

member / 2, memberchk / 2