Swift Introduction | Values, Variables, and Operations | Literals
Values and variables are fundamental programming concepts. This article begins with values written directly in source code.
A value written directly in source code is called a literal. Literal syntax is similar in many programming languages.
Numeric Literals
Write ordinary numbers directly, such as 123 or 0.45. Swift also supports several other forms.
Separating Digits with Underscores
Long numbers can be difficult to read. Swift lets you separate digits with underscores (_) instead of commas. You can also add leading zeros to align digits.
Example: 0012_3456_7890 (the same as 1234567890)
Binary, Octal, and Hexadecimal Numbers
In addition to decimal numbers, you can write binary, octal, and hexadecimal values.
| Base | Description | Example |
|---|---|---|
| Binary | Add 0b at the beginning. |
0b11011 |
| Octal | Add 0o at the beginning. The second character is the letter o. |
0o7623 |
| Hexadecimal | Add 0x at the beginning. Use digits 0-9 and letters A-F. |
0x5fa3 |
Text Literals
Write text between double quotation marks (").
Example: "Hello", "Hello there"
Escape Sequences
Some characters cannot be written directly in a text literal. Use a backslash (\) to write characters such as quotation marks and line breaks.
| Sequence | Description |
|---|---|
| \" | Double quotation mark (") |
| \\ | Backslash (\) |
| \t | Horizontal tab |
| \r | Carriage return |
| \n | Line feed |
| \0 | Null character |
Example: "This is a \"double\\quote\" symbol\n"
Including Variables
Include a variable in a literal with \(variable).
Example: "Display \(str) here"
Boolean Literals
Boolean values represent one of two states. Swift provides the literals true and false.