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# memberchk(+Term, ?List)

Succeeds if Term is a member of the list List.
*+Term*
- Prolog term.
*?List*
- List or a variable.

## Description

Unifies Term with the first matching element of the list List.
If List is not instantiated, memberchk/2 binds List to a new partial
list containing an element Term.

The definition of this Prolog library predicate is:

memberchk(X,[X|_]) :- !.
memberchk(X,[_|T]):- memberchk(X,T).

This predicate does not perform any type testing functions.
### Modes and Determinism

- memberchk(+, +) is semidet
- memberchk(+, -) is det

### Fail Conditions

Fails if Term is not a member of the list List.
### Resatisfiable

No.
## Examples

Success:
memberchk(0,[1,B,2]). (gives B=0).
memberchk(1,[1,X]). (gives X=_g76).
memberchk(1,X), memberchk(2,X).
(gives X=[1,2|_g98]).
Fail:
memberchk(0,[1,2,3,4]).

## See Also

member / 2