Instance Method

# max(by:)

Returns the maximum element in the sequence, using the given predicate as the comparison between elements.

## Parameters

`areInIncreasingOrder`

A predicate that returns `true` if its first argument should be ordered before its second argument; otherwise, `false`.

## Return Value

The sequence’s maximum element if the sequence is not empty; otherwise, `nil`.

## Discussion

The predicate must be a strict weak ordering over the elements. That is, for any elements `a`, `b`, and `c`, the following conditions must hold:

• `areInIncreasingOrder(a, a)` is always `false`. (Irreflexivity)

• If `areInIncreasingOrder(a, b)` and `areInIncreasingOrder(b, c)` are both `true`, then `areInIncreasingOrder(a, c)` is also `true`. (Transitive comparability)

• Two elements are incomparable if neither is ordered before the other according to the predicate. If `a` and `b` are incomparable, and `b` and `c` are incomparable, then `a` and `c` are also incomparable. (Transitive incomparability)

This example shows how to use the `max(by:)` method on a dictionary to find the key-value pair with the highest value.

Complexity: O(n), where n is the length of the sequence.

### Finding Elements

`func contains(where: ((key: Key, value: Value)) -> Bool) -> Bool`

Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.

`func allSatisfy(((key: Key, value: Value)) -> Bool) -> Bool`

Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.

`func first(where: ((key: Key, value: Value)) -> Bool) -> (key: Key, value: Value)?`

Returns the first element of the sequence that satisfies the given predicate.

`func firstIndex(where: ((key: Key, value: Value)) -> Bool) -> Index?`

Returns the first index in which an element of the collection satisfies the given predicate.

`func min(by: ((key: Key, value: Value), (key: Key, value: Value)) -> Bool) -> (key: Key, value: Value)?`

Returns the minimum element in the sequence, using the given predicate as the comparison between elements.