Structure

Character

A single extended grapheme cluster that approximates a user-perceived character.

Overview

The Character type represents a character made up of one or more Unicode scalar values, grouped by a Unicode boundary algorithm. Generally, a Character instance matches what the reader of a string will perceive as a single character. Strings are collections of Character instances, so the number of visible characters is generally the most natural way to count the length of a string.

let greeting = "Hello! 🐥"
print("Length: \(greeting.count)")
// Prints "Length: 8"

Because each character in a string can be made up of one or more Unicode code points, the number of characters in a string may not match the length of the Unicode code point representation or the length of the string in a particular binary representation.

print("Unicode code point count: \(greeting.unicodeScalars.count)")
// Prints "Unicode code point count: 15"

print("UTF-8 representation count: \(greeting.utf8.count)")
// Prints "UTF-8 representation count: 18"

Every Character instance is composed of one or more Unicode code points that are grouped together as an extended grapheme cluster. The way these code points are grouped is defined by a canonical, localized, or otherwise tailored Unicode segmentation algorithm.

For example, a country’s Unicode flag character is made up of two regional indicator code points that correspond to that country’s ISO 3166-1 alpha-2 code. The alpha-2 code for The United States is “US”, so its flag character is made up of the Unicode code points "\u{1F1FA}" (REGIONAL INDICATOR SYMBOL LETTER U) and "\u{1F1F8}" (REGIONAL INDICATOR SYMBOL LETTER S). When placed next to each other in a Swift string literal, these two code points are combined into a single grapheme cluster, represented by a Character instance in Swift.

let usFlag: Character = "\u{1F1FA}\u{1F1F8}"
print(usFlag)
// Prints "🇺🇸"

For more information about the Unicode terms used in this discussion, see the Unicode.org glossary. In particular, this discussion mentions extended grapheme clusters and Unicode scalar values.

Topics

Creating a Character

In addition to creating a character from a single-character string literal, you can also convert a unicode scalar value or single-character string.

init(String)

Creates a character from a single-character string.

Writing to a Text Stream

func write<Target>(to: inout Target)

Writes the character into the given output stream.

Comparing Characters

static func !=(Character, Character)

Returns a Boolean value indicating whether two values are not equal.

Beta
static func <=(Character, Character)

Returns a Boolean value indicating whether the value of the first argument is less than or equal to that of the second argument.

Beta
static func >(Character, Character)

Returns a Boolean value indicating whether the value of the first argument is greater than that of the second argument.

Beta
static func >=(Character, Character)

Returns a Boolean value indicating whether the value of the first argument is greater than or equal to that of the second argument.

Beta

Working with a Character's Unicode Values

init(Unicode.Scalar)

Creates a character containing the given Unicode scalar value.

Beta

Creating a Range Expression

static func ..<(Character)

Returns a partial range up to, but not including, its upper bound.

Beta
static func ...(Character)

Returns a partial range extending upward from a lower bound.

Beta
static func ...(Character)

Returns a partial range up to, and including, its upper bound.

Beta

Describing a Character

var debugDescription: String

A textual representation of the character, suitable for debugging.

var customMirror: Mirror

A mirror that reflects the Character instance.

var hashValue: Int

The character’s hash value.

Infrequently Used Functionality

See Also

Strings and Characters

struct String

A Unicode string value that is a collection of characters.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

Learn more about using Apple's beta software