Instance Method

# first(where:)

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

## Parameters

`predicate`

A closure that takes an element of the sequence as its argument and returns a Boolean value indicating whether the element is a match.

## Return Value

The first element of the sequence that satisfies `predicate`, or `nil` if there is no element that satisfies `predicate`.

## Discussion

The following example uses the `first(where:)` method to find the first negative number in an array of integers:

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

### Finding Entities

`func contains(Entity) -> Bool`

Returns a Boolean value indicating whether the sequence contains the given element.

`func contains(where: (Entity) -> Bool) -> Bool`

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

`func allSatisfy((Entity) -> Bool) -> Bool`

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

`var first: Entity?`

The first element of the collection.

`func max(by: (Entity, Entity) -> Bool) -> Entity?`

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

`func min(by: (Entity, Entity) -> Bool) -> Entity?`

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

`func randomElement() -> Entity?`

Returns a random element of the collection.

`func randomElement<T>(using: inout T) -> Entity?`

Returns a random element of the collection, using the given generator as a source for randomness.