Returns a Boolean value that indicates whether a given key is in a dictionary.
- iOS 2.0+
- macOS 10.0+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
- Core Foundation
The dictionary to examine.
The key for which to find matches in
the. The key hash and equal callbacks provided when the dictionary was created, are used to compare. If the hash callback is
keyis treated as a pointer and converted to an integer. If the equal callback is
NULL, pointer equality (in C, ==) is used. If
key, or any of the keys in the dictionary, is not understood by the equal callback, the behavior is undefined.
key is in the dictionary, otherwise