# 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.

`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`

.

## Returns

`true`

if this sequence and `other`

contain equivalent items, using `areEquivalent`

as the equivalence test; otherwise, `false.`

## Overview

At least one of the sequences must be finite.

The predicate must be a *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)