swift-字符串的使用

// 定义字符串

let string = "Hello World"

 

let string1 : String

string1 = "Hello"

 

 

// 字符串的遍历

for c in string1.characters {

    print(c)

}

 

// 字符串的拼接

// 1.两个字符串之间的拼接

let str1 = "my name"

let str2 = " is why"

let str3 = str1 + str2

 

// 2.字符串和其他类型的拼接

let age = 18

let name = "why"

let height = 1.88

 

// 如果字符串中出现了变量:\(标识符的名称)

let info = "My name is \(name), age is \(age), height is \(height)"

 

// 3.字符串的格式化

// 03:04

let min = 3

let second = 4

var time = "\(min):\(second)"

time = String(format: "%02d:%02d", arguments: [min, second])

 

// 4.字符串的截取

let url = "www.520it.com"

 

let url1 = (url as NSString).substringToIndex(3)

let url2 = (url as NSString).substringFromIndex(10)

let range = NSRange(location: 4, length: 5)

let url3 = (url as NSString).substringWithRange(range)