Swift Character

A character in Swift is a single-character string literal with the data type Character.

The following example lists two character instances:

import Cocoa

let char1: Character = "A"
let char2: Character = "B"

print("char1 is \(char1)")
print("char2 is \(char2)")

The output of the above program is:

char1 is A
char2 is B

If you try to store more characters in a constant of type Character, the program will throw an error, as shown below:

import Cocoa

// The following assignment will cause an error in Swift
let char: Character = "AB"

print("Value of char \(char)")

The output of the above program is:

error: cannot convert value of type 'String' to specified type 'Character'
let char: Character = "AB"

Empty Character Variable

In Swift, you cannot create an empty Character variable or constant:

import Cocoa

// The following assignment will cause an error in Swift
let char1: Character = ""
var char2: Character = ""

print("char1 is \(char1)")
print("char2 is \(char2)")

The output of the above program is:

error: cannot convert value of type 'String' to specified type 'Character'
let char1: Character = ""
                       ^~
error: cannot convert value of type 'String' to specified type 'Character'
var char2: Character = ""

Iterating Over Characters in a String

The String type in Swift represents a sequence of Character values. Each character value represents a Unicode character.

In Swift 4, attributes and methods that were accessed through characters in Swift 3 can now be directly called on the String object, for example:

In Swift 3:

import Cocoa

for ch in "tutorialpro".characters {
    print(ch)
}

In Swift 4:

import Cocoa

for ch in "tutorialpro" {
    print(ch)
}

The output of the above program is:

R
u
n
o
o
b

Concatenating Characters to a String

The following example demonstrates how to concatenate characters to a string using the append() method of String:

import Cocoa

var varA: String = "Hello "
let varB: Character = "G"

varA.append(varB)

print("varC = \(varA)")

The output of the above program is:

varC = Hello G