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msort(+List1, -List2)

Succeeds if List2 has the same elements as List1 and is sorted.
List1
List.
List2
List or variable.

Description

List1 is sorted according to standard term ordering, (without removing duplicates in the sense of ==/2) and unified with List2.

The sort is done according to the standard ordering of terms. Duplicates are not removed. See compare/3 for this standard ordering. Note in particular that numbers are first ordered by their type (integer, float, etc) and only then by their magnitude, i.e. sorting numbers of different types may not give the expected result.

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

Modes and Determinism

Exceptions

(4) instantiation fault
List1 is not instantiated.
(5) type error
List1 is not a list.

Examples

Success:
      msort([3,2,1,2,3],[1,2,2,3,3]).
      msort([2,4,6],L).         (gives L=[2,4,6]).
      msort([2,4,6,1,7,3],L).   (gives L=[1,2,3,4,6,7]).

Fail:
      msort([1,5,3,7],[1,3,7,5]).

Error:
      msort(List1,List2).         (Error 4).
      msort("[1]",L).             (Error 5).



See Also

compare / 3, sort / 2, sort / 4, number_sort / 2