5.Swift 字符串的小技巧

在之前我就写过一篇文章关于可以插入字符的文章23.使用Swift自带的join函数拼接字符串, 这里讲的是使用join函数在每个字符之间插入自定义的字符.

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1.获取字符串的索引

let sayHello = "Hello word!"// 开始的characters字符, 输出的结果为: Hprint(sayHello[sayHello.startIndex])// 结尾的characters字符, 输出的结果为: !print(sayHello[sayHello.endIndex.predecessor()])// 第7个characters的字符, 输出的结果为: oprint(sayHello[sayHello.startIndex.advancedBy(7)])// 遍历sayHello的characters的索引范围, 输出的结果为: H-e-l-l-o- -w-o-r-d-!-for index in sayHello.characters.indices {    // 在每个索引字符后面添加一个字符    print("\(sayHello[index])", terminator: "-")}

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2.插入和删除字符

var welcome = "hello"// 插入字符"!"到welcome最后的索引welcome.insert("!", atIndex: welcome.endIndex)print(welcome)// 插入字符" wrod"在welcome最后的索引前一个welcome.insertContentsOf(" word".characters, at: welcome.endIndex.predecessor())print(welcome)// 删除在welcome最后的索引前一个welcome.removeAtIndex(welcome.endIndex.predecessor())print(welcome)// 删除规定范围内的字符let range = welcome.endIndex.advancedBy(-5) ..< welcome.endIndexwelcome.removeRange(range)print(welcome)

输出结果

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3.判断字符

在Swift当中有分为三种对比, 字符内容相等, 字符后缀相等, 字符后缀相等.

字符内容判断

let hello = "hello"let hi = "hello"if hello == hi {    print("These two strings are considered equal")}

字符前缀判断

let personName = [    "person name 1 : xiaoming",    "person name 2 : honghong",    "person name 3 : zhangsan",    "person name 4 : lisi",    "person name 5 : huangwu",    "person name 6 : datou"]var personNumber = 0for name in personName {    if name.hasPrefix("person") {        ++personNumber    }}print(personNumber)// 输出的结果为: 6

字符串后缀判断

let personLastName = [    "xiaoming chen",    "xiaohong chen",    "zhangsan li",    "baibai chen"]var personLastNameNumber = 0for lastName in personLastName {    if lastName.hasSuffix("chen") {        ++personLastNameNumber    }}print(personLastNameNumber)// 输出结果为: 3

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好了, 这次就讲到这里, 谢谢