Swift literally

Swift literally

Literally, it refers to values like a specific number, string, or Boolean value that can directly point out your own type and assign values to variables. For example, here's what:

let aNumber = 3         //整型字面量
let aString = "Hello"   //字符串字面量
let aBool = true        //布尔值字面量

The literal amount of the integer

The literal quantity of an integer can be a heteth, binary, octal, or heteen constant. T he binary prefix is 0b, the octal prefix is 0o, the hex prefix is 0x, and the octal has no prefix:

Here are some examples of integer literal quantities:

let decimalInteger = 17           // 17 - 十进制表示
let binaryInteger = 0b10001       // 17 - 二进制表示
let octalInteger = 0o21           // 17 - 八进制表示
let hexadecimalInteger = 0x11     // 17 - 十六进制表示

Floating-point literal quantity

Floating-point literal quantities have integer parts, adget points, small parts and exponential parts.

Unless specifically specified, the default inference type for floating-point literal quantities is Double in the Swift standard library type, which represents a 64-bit floating-point number.

Floating-point literals are expressed by default in a hex (no prefix) or hex (with a prefix 0x).

A hex floating-point literal quantity consists of a string of hex digits followed by a small part or an exponential part (or both). T he hemissal component consists of a few points . C onsists of a string of hedding numbers. T he exponential portion consists of a string of prefixes followed by the lowercase letter e, which represents the number before e multiplied by several squares of 10. For example, 1.25e2 represents 1.25 ⨉ 10^2, or 125.0, and 1.25e-2 means 1.25 ⨉10^-2, or 0.0125.

Hex floating-point literal quantity consists of the prefix 0x followed by the optional hexaad component and the hex index portion. T he heteered part consists of a string of hetelude points followed by hete sixteen-digit numbers. T he exponential portion consists of a string of prefixes followed by the lowercase p prefix, which represents the number before p multiplied by several squares of 2. F or example, 0xFp2 represents 15 ⨉ 2^2, or 60, and 0xFp-2 means 15 ⨉ 2^-2, or 3.75.

Negative floating-point literals consist of a unit operator minus sign - and floating-point literals, such as -42.5.

Floating-point literals allow the use of underscores to enhance the readability of numbers, and underscores are ignored by the system, so they do not affect literal values. S imilarly, you can add 0 before the number without affecting the literal value.

Here are some examples of floating-point literal quantities:

let decimalDouble = 12.1875       //十进制浮点型字面量
let exponentDouble = 1.21875e1    //十进制浮点型字面量
let hexadecimalDouble = 0xC.3p0   //十六进制浮点型字面量

String literally

String literally consists of a string of characters wrapped in double quotes in the form of the following:

"characters"

String literals cannot contain un escaped double quotes ("), un escaped anti-slashes (\), carriage returns, or line breaks.

Here's a simple example of a string literally:

import Cocoa

let stringL = "Hello\tWorld\n\nW3Cschool教程官网：\'http://www.w3cschool.cn\'"
print(stringL)

The above procedures are performed as follows:

Hello	World

W3Cschool教程官网：'http://www.w3cschool.cn'

Boolean literal quantity

The default type for Boolean literal quantities is Bool.

Boolean values literally have three values, which are Swift's reserved keywords:

• true means true.

• false indicates false.

• nil indicates that there is no value.