Returns true if the collection contains an element equal to element.
Returns true if the collection contains an element equal to element.
This operation will check each element in order for being equal to element, unless it has a more efficient way to find an element equal to element.
The equality used to determine whether element is equal to an element of the iterable defaults to the Object.operator== of the element.
Some types of iterable may have a different equality used for its elements.
For example, a Set may have a custom equality
(see Set.identical) that its contains
uses.
Likewise the Iterable
returned by a Map.keys call
should use the same equality that the Map
uses for keys.