1: 字符串的定義

//1: 字符串的定義
var str = "Hello, playground"
//在實(shí)際開發(fā)過程中經(jīng)常用可選項(xiàng)配合
var string1: String?
string1 = "xiaoma"

2:兩個字符串比較

//2:兩個字符串比較
// == 完美拋棄煩人的 isEqualToString
if  string1 == str {
    print("相同的字符串")
} else {
    print("不相同的字符串")
}
string1 == str
string1 ?? "" < str //必須解包   給個默認(rèn)值
string1! > str  //必須解包   強(qiáng)制解包
string1 != str

3:字符串前綴,后綴

//3:字符串前綴,后綴
let arrayTest = ["cc","cDYZ","kuke","987","gaven","adofe","vegl","inhe"];
for s in arrayTest {
    if s.hasPrefix("c") {//前綴
        print(s)
    }
    if s.hasSuffix("e") {//后綴
        print(s)
    }
}

4:連接字符串和字符

//4:連接字符串和字符
let string3 = "hello"
let string4 = " world"
var welcome = string3 + string4
//append也可以
welcome.append(" dengyazhou")

//5:訪問和修改字符串

//5:訪問和修改字符串
var string5 = "Swift hello world"
string5.startIndex //String.Index
print(string5[string5.startIndex])

//5.1刪除字符串中特定的字符
//拿到開始索引
let index = string5.index(string5.startIndex, offsetBy: 3) //在0的基礎(chǔ)上，往后偏移三位，下標(biāo)為3，0開始
print(string5[index]) //f
string5.remove(at: index)
print(string5[index])
//結(jié)束索引
let index2 = string5.index(string5.startIndex, offsetBy: 5)
//這個方法是傳String.index的類型
//其中特別說明一下 index...index2 代表區(qū)間  這個經(jīng)常用在for-in循環(huán)
//string5.removeSubrange(index...index2)

//5.2字符串替換
//string5.replaceSubrange(index...index2, with: "CC")
//print(string5)
//string5.replacingOccurrences(of: "o", with: "P") //用P替換o

let index3 = string5.index(string5.startIndex, offsetBy: 6)
//5.3字符串插入
//string5.insert(contentsOf: "Nice", at: index3) //插入一個字符串
//string5.insert("N", at: index3) //插入一個Character
//print(string5)

6:大寫和小寫字符串

//6:大寫和小寫字符串
let string6 = "hello, world ni hAo"
//全部大寫
string6.uppercased()
//首字母大寫,其他都小寫(根據(jù)標(biāo)點(diǎn)來)
string6.capitalized
//全部小寫
string6.lowercased()

7:字符轉(zhuǎn)字符串

//7:字符轉(zhuǎn)字符串
var characters : [Character] = ["H","e","l","l","o","??","H","o","o","i","i","??","J","o","o","i","i"]
let string7 = String(characters)
//上面組合,下面按照??分開
string7.split(separator: "??")

Swift HelloWorld(一)
Swift 基本數(shù)據(jù)類型(二)
Swift 字符串(三)
Swift 閉包(Closures)(四)
Swift 集合類型(五)
Swift 函數(shù)(六)
Swift 類(七)
Swift 結(jié)構(gòu)體、枚舉(八)
Swift 屬性(九)
Swift 方法(十)