A string is a sequence of characters, such as "Hello World!".
Strings use the String data type,
although you don't need to specify the data type to use a string.
var s1 = "Hello World!"
Strings can include any Unicode characters.
To write single-byte Unicode characters,
you must include \x before the two hexadecimal digits.
Two-byte Unicode characters are prefixed with \u before four hexadecimal digits,
and four-byte Unicode characters have \U written before eight hexadecimal digits.
The following code shows an example of using Unicode characters.
let percentage = "\x{25}" let snowflake = "\u{2744}" let heart = "\u{0001F497}"
Strings are collections of characters, and characters have their own data
type called Character.
Characters can have only one character, and you
must explicitly declare your variable or constant as a Character.
The following code shows how to declare a Character type value.
let c1:Character = "A"
In Swift, you can combine strings and characters to create longer strings.
The following code shows how to create an alphabet string based on characters and strings.
//Declare characters and strings let c1:Character = "A" let c2:Character = "B" let c3:Character = "C" let c4:Character = "D" let c5:Character = "E" let s2 = "FGHIJ" //Declare an empty string var alphabet = String() //Concatenate strings, characters and literals alphabet = c1 + c2 + c3 + c4 + c5 + s2 + "KLMNOP"
We can compare two strings with comparison operator ==.
It returns a boolean (true or false) value back.
alphabet == "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
To print out different variables, constants, literals, and expressions in a string, use string interpolation.
String interpolation puts a forward slash \
in front of a variable name in parentheses.
let i:Int = -25
let f:Float = 3.14
let d:Double = 99.99
let b:Bool = true
println("i = \(i), f = \(f), d = \(d), b = \(b)")