Check if all numbers in a list are different in prolog

Question

I want to create a rule in prolog that checks if there\'s a repeated number in a list.

For example:

• for [1,2,3,4] it will return tru

Answer 1

Very Simple Answer...

The code:

unique([]). unique([_,[]]). unique([H|T]):-not(member(H,T)),unique(T).

Tests:

?-unique([1,2,3,4]). true. ?-unique([1,2,3,3]). false. ?-unique([a,b,12,d]). true ?-unique([a,b,a]). false