# Strings and Text Create and process strings of Unicode characters, use regular expressions to find patterns, and perform natural language analysis of text. ## Topics ### Strings [String Encodings](/documentation/Foundation/1497293-string-encodings) Constants for encoding standards used when converting raw data to and from string representations. ### Strings [`NSString`](/documentation/Foundation/NSString) A static, plain-text Unicode string object. [`NSMutableString`](/documentation/Foundation/NSMutableString) A dynamic plain-text Unicode string object. ### Strings with Metadata [`AttributedString`](/documentation/Foundation/AttributedString) A value type for a string with associated attributes for portions of its text. [`AttributedSubstring`](/documentation/Foundation/AttributedSubstring) A portion of an attributed string. [Attributed String Supporting Types](/documentation/Foundation/attributed-string-supporting-types) Types that the attributed string, attributed substring, and helper types extend or conform to, for sharing common functionality. [`NSAttributedString`](/documentation/Foundation/NSAttributedString) A string of text that manages data, layout, and stylistic information for ranges of characters to support rendering. [`NSMutableAttributedString`](/documentation/Foundation/NSMutableAttributedString) A mutable string with associated attributes (such as visual style, hyperlinks, or accessibility data) for portions of its text. ### Strings with Metadata [`NSAttributedString`](/documentation/Foundation/NSAttributedString) A string of text that manages data, layout, and stylistic information for ranges of characters to support rendering. [`NSMutableAttributedString`](/documentation/Foundation/NSMutableAttributedString) A mutable string with associated attributes (such as visual style, hyperlinks, or accessibility data) for portions of its text. ### Characters [`CharacterSet`](/documentation/Foundation/CharacterSet) A set of Unicode character values for use in search operations. ### Characters [`NSCharacterSet`](/documentation/Foundation/NSCharacterSet) An object representing a fixed set of Unicode character values for use in search operations. [`NSMutableCharacterSet`](/documentation/Foundation/NSMutableCharacterSet) An object representing a mutable set of Unicode character values for use in search operations. [`unichar`](/documentation/Foundation/unichar) Type for UTF-16 code units. ### Pattern Matching [`Scanner`](/documentation/Foundation/Scanner) A string parser that scans for substrings or characters in a character set, and for numeric values from decimal, hexadecimal, and floating-point representations. [`NSRegularExpression`](/documentation/Foundation/NSRegularExpression) An immutable representation of a compiled regular expression that you apply to Unicode strings. [`NSDataDetector`](/documentation/Foundation/NSDataDetector) A specialized regular expression object that matches natural language text for predefined data patterns. [`NSTextCheckingResult`](/documentation/Foundation/NSTextCheckingResult) An occurrence of textual content found during the analysis of a block of text, such as when matching a regular expression. [`NSNotFound`](/documentation/Foundation/NSNotFound-4qp9h) A value indicating that a requested item couldn’t be found or doesn’t exist. ### Spelling and Grammar [`NSSpellServer`](/documentation/Foundation/NSSpellServer) A server that your app uses to provide a spell checker service to other apps running in the system. [`NSSpellServerDelegate`](/documentation/Foundation/NSSpellServerDelegate) The optional methods implemented by the delegate of a spell server. ### Localization [`Locale`](/documentation/Foundation/Locale) Information about linguistic, cultural, and technological conventions for use in formatting data for presentation. [`NSOrthography`](/documentation/Foundation/NSOrthography) A description of the linguistic content of natural language text, typically used for spelling and grammar checking. [`NSLocalizedString(_:tableName:bundle:value:comment:)`](/documentation/Foundation/NSLocalizedString(_:tableName:bundle:value:comment:)) Returns a localized string from a table that Xcode generates for you when exporting localizations. [`LocalizedStringResource`](/documentation/Foundation/LocalizedStringResource) A reference to a localizable string, accessible from another process. [`CustomLocalizedStringResourceConvertible`](/documentation/Foundation/CustomLocalizedStringResourceConvertible) A type that provides an out-of-process localizable description. [`URLResource`](/documentation/Foundation/URLResource) A resource located at a particular file URL within a bundle. ### Localization [`NSLocale`](/documentation/Foundation/NSLocale) Information about linguistic, cultural, and technological conventions for use in formatting data for presentation. [`NSOrthography`](/documentation/Foundation/NSOrthography) A description of the linguistic content of natural language text, typically used for spelling and grammar checking. [`NSLocalizedString`](/documentation/Foundation/NSLocalizedString) Returns a localized version of a string from the default table, which Xcode autogenerates when exporting localizations. [`NSLocalizedStringFromTable`](/documentation/Foundation/NSLocalizedStringFromTable) Returns a localized version of a string from the table that you specify, which Xcode autogenerates when exporting localizations. [`NSLocalizedStringFromTableInBundle`](/documentation/Foundation/NSLocalizedStringFromTableInBundle) Returns a localized version of a string from the table and bundle that you specify, which Xcode autogenerates when exporting localizations. [`NSLocalizedStringWithDefaultValue`](/documentation/Foundation/NSLocalizedStringWithDefaultValue) Returns a localized version of a string identified by a key in the table that you specify, which Xcode autogenerates when exporting localizations. ### Deprecated [`NSLinguisticTagger`](/documentation/Foundation/NSLinguisticTagger) Analyze natural language text to tag part of speech and lexical class, identify names, perform lemmatization, and determine the language and script. [Deprecated String Encodings](/documentation/Foundation/1497268-deprecated-string-encodings) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)