NSMutableAttributedString is a subclass of NSAttributedString that allows the contents and attributes of the string to be altered after the object has been initialized, which is normally not possible with its immutable superclass.

@interface NSMutableAttributedString : NSAttributedString
// Accessor Methods
- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range;
- (void)setAlignment:(NSTextAlignment)alignment range:(NSRange)range;
- (void)setAttributedString:(NSAttributedString *)attrString;
// Instance Methods
- (void)appendAttributedString:(NSAttributedString *)attrString;
- (void)addAttribute:(NSString *)name value:(id)value range:(NSRange)range;
- (void)addAttributes:(NSDictionary *)attrs range:(NSRange)range;
- (void)applyFontTraits:(NSFontTraitMask)traitMask range:(NSRange)range;
- (void)beginEditing;
- (void)deleteCharactersInRange:(NSRange)range;
- (void)endEditing;
- (void)fixAttachmentAttributeInRange:(NSRange)range;
- (void)fixAttributesInRange:(NSRange)range;
- (void)fixFontAttributeInRange:(NSRange)range;
- (void)fixParagraphStyleAttributeInRange:(NSRange)range;
- (void)insertAttributedString:(NSAttributedString *)attrString atIndex:(unsigned)loc;
- (NSMutableString *)mutableString;
- (BOOL)readFromURL:(NSURL *)url options:(NSDictionary *)options documentAttributes:(NSDictionary **)dict;
- (void)removeAttribute:(NSString *)name range:(NSRange)range;
- (void)replaceCharactersInRange:(NSRange)range withAttributedString:(NSAttributedString *)attrString;
- (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)str;
- (void)subscriptRange:(NSRange)range;
- (void)superscriptRange:(NSRange)range;
- (void)unscriptRange:(NSRange)range;
- (void)updateAttachmentsFromPath:(NSString *)path;

Subclasses

NSTextStorage