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sort(+List1, ?List2)

Succeeds if List2 is the strictly ordered, no duplicates version of List1.
+List1
List.
?List2
List or variable.

Description

List1 is sorted strictly according to standard term ordering (removing duplicates in the sense of ==/2), and unified with List2.

The sort is done according to the standard ordering of terms. See compare/3 for this standard ordering.

Note sort(L1,L2) is equivalent to sort(0,<,L1,L2). sort(L1,L2) differs from msort(L1,L2) in that it removes duplicates.

Fail Conditions

Fails if List2 does not unify with the sorted list version of List1.

Resatisfiable

No.

Examples

Success:
      sort([3,1,6,7,2],S).     (gives S=[1,2,3,6,7]).
      sort([1,3,2,3,4,1],S).   (gives S=[1,2,3,4]).
      sort([f(1,3),h(2,1)],S). (gives S=[f(1,3),h(2,1)]).
      sort(["b",2.0,a(1),1,a],S).
                            (gives S=[2.0,1,"b",a,a(1)]).
Fail:
      sort([2,1,3,4],[2,1,3,4]).

See Also

compare / 3, msort / 2, sort / 4