NSMutable class declares the programmatic interface to objects that manage a modifiable set of Unicode characters. You can add or remove characters from a mutable character set as numeric values in
NSRange structures or as character values in strings, combine character sets by union or intersection, and invert a character set.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
Mutable character sets are less efficient to use than immutable character sets. If you don’t need to change a character set after creating it, create an immutable copy with
copy and use that.
NSMutable defines no primitive methods. Subclasses must implement all methods declared by this class in addition to the primitives of
NSCharacter. They must also implement