String literals in Swift are delimited with double quotes ("):

let greeting = "Hello!"  // greeting's type is String

Characters can be initialized from string literals, as long as the literal contains only one grapheme cluster:

let chr: Character = "H" // valid
let chr2: Character = "😊" // valid
let chr3: Character = "abc" // invalid - multiple grapheme clusters

String Interpolation

String interpolation allows injecting an expression directly into a string literal. This can be done with all types of values, including strings, integers, floating point numbers and more.

The syntax is a backslash followed by parentheses wrapping the value: \\(value). Any valid expression may appear in the parentheses, including function calls.

let number = 5
let interpolatedNumber = "\\(number)"  // string is "5"
let fortyTwo = "\\(6 * 7)"             // string is "42"

let example = "This post has \\(number) view\\(number == 1 ? "" : "s")"
// It will output "This post has 5 views" for the above example.
// If the variable number had the value 1, it would output "This post has 1 view" instead.

For custom types, the default behavior of string interpolation is that "\\(myobj)" is equivalent to String(myobj), the same representation used by print(myobj). You can customize this behavior by implementing the [CustomStringConvertible protocol](https://developer.apple.com/library/ios/documentation/Swift/Reference/Swift_CustomStringConvertible_Protocol/index.html) for your type.

For Swift 3, in accordance with SE-0089, String.init<T>(_:) has been renamed to String.init<T>(describing:).

The string interpolation "\\(myobj)" will prefer the new String.init<T: LosslessStringConvertible>(_:) initializer, but will fall back to init<T>(describing:) if the value is not LosslessStringConvertible.

Special Characters

Certain characters require a special escape sequence to use them in string literals:

Character | Meaning — | — \\0 | the null character \\\\ | a plain backslash, \\\\ \\t | a tab character \\v | a vertical tab \\r | a carriage return \\n | a line feed (“newline”) \\" | a double quote, " \\' | a single quote, \\' \\u{n} | the Unicode code point n (in hexadecimal)

Example:

let message = "Then he said, \\"I \\u{1F496} you!\\""

print(message) // Then he said, "I 💖 you!"