Contents

elementsEqual(_:by:)

Returns a Boolean value indicating whether this sequence and another sequence contain equivalent elements in the same order, using the given predicate as the equivalence test.

Declaration

func elementsEqual<OtherSequence>(_ other: OtherSequence, by areEquivalent: (Self.Element, OtherSequence.Element) throws -> Bool) rethrows -> Bool where OtherSequence : Sequence

Parameters

  • other:

    A sequence to compare to this sequence.

  • areEquivalent:

    A predicate that returns true if its two arguments are equivalent; otherwise, false.

Return Value

true if this sequence and other contain equivalent items, using areEquivalent as the equivalence test; otherwise, false.

Discussion

At least one of the sequences must be finite.

The predicate must be an equivalence relation over the elements. That is, for any elements a, b, and c, the following conditions must hold:

  • areEquivalent(a, a) is always true. (Reflexivity)

  • areEquivalent(a, b) implies areEquivalent(b, a). (Symmetry)

  • If areEquivalent(a, b) and areEquivalent(b, c) are both true, then areEquivalent(a, c) is also true. (Transitivity)