Swift - String, Character

String,Character

String 在 Swift 中使用双引号（”）作为界限：

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

Character 可以从string初始化，只要只包含一个字符：

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

字符串插入值

String interpolation 允许注入一个表达式，可以是任何值，包括字符串，整数，浮点数和其他各种。

语法是用一个斜杠，后面紧跟着一对括号括起来的值：(value)。任何有效的表达式都可以出现在括号里，包括函数调用。

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.

特殊的字符

• 
  空字符
• 
  斜杠
• t
  tab符
• v
  纵向tab
• r
  回车符
• n
  换行符
• ”
  双引号
• ’
  单引号
• u{n}
  Unicode 符号

比如：

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

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