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➤微信公衆號：山青詠芝（shanqingyongzhi）
➤博客園地址：山青詠芝（https://www.cnblogs.com/strengthen/ ）
➤GitHub地址：https://github.com/strengthen/LeetCode
➤原文地址：https://www.cnblogs.com/strengthen/p/9798159.html
➤若是連接不是山青詠芝的博客園地址，則多是爬取做者的文章。
➤原文已修改更新！強烈建議點擊原文地址閱讀！支持做者！支持原創！
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Swift中沒法再使用傳統形式的for循環。git
1 //傳統for循環形式不適用於Swift 2 for（單次表達式;條件表達式;末尾循環體）{中間循環體；}
字符串遍歷方法1：使用該indices屬性能夠訪問字符串中各個字符的全部索引。github
1 let str = "Strengthen!" 2 for index in str.indices { 3 print("\(str[index]) ", terminator: "") 4 } 5 // Prints "S t r e n g t h e n ! "
字符串遍歷方法2：每一個String值都有一個關聯的索引類型，String.Index它對應Character於字符串中每一個值的位置。要訪問遠離給定索引的索引，能夠使用該index(_:offsetBy:)方法而不是屢次調用其中一種方法。您能夠使用下標語法來訪問Character特定String索引。數組
1 extension String { 2 //subscript函數能夠檢索數組中的值 3 //按照索引方式讀取字符 4 subscript (_ i: Int) -> Character { 5 //讀取字符 6 get {return self[index(startIndex, offsetBy: i)]} 7 } 8 } 9 10 //方式1 11 let str = "Strengthen!" 12 for num in 0..<str.count 13 { 14 let char:Character = str[str.index(str.startIndex,offsetBy: num)] 15 print("\(char) ", terminator: "") 16 } 17 //Prints "S t r e n g t h e n ! " 18 19 //方式2 20 for num in 0..<str.count 21 { 22 let char:Character = str[num] 23 print("\(char) ", terminator: "") 24 } 25 //Prints "S t r e n g t h e n ! "
字符串遍歷方法3：遍歷字符串的每個字符微信
1 let str = "Strengthen!" 2 for char in str.characters { 3 print("\(char) ", terminator: "") 4 } 5 //Prints "S t r e n g t h e n ! "
字符串遍歷方法4：遍歷字符串的每個字符對應ASCII的整數值ide
1 let str = "Strengthen" 2 var strUnicodeScalars = Array(str.utf8) 3 print(strUnicodeScalars) 4 //Prints [83, 116, 114, 101, 110, 103, 116, 104, 101, 110] 5 for charNum in strUnicodeScalars 6 { 7 print("\(charNum) ", terminator: "") 8 } 9 //Prints "83 116 114 101 110 103 116 104 101 110"
倒序遍歷字符串方法1：reversed()函數
1 let str = "Strengthen!" 2 for char in str.reversed() { 3 print("\(char) ", terminator: "") 4 } 5 //Prints ! n e h t g n e r t S
倒序遍歷字符串方法2：stride函數 -返回一個任意可變步長類型值的序列。可變步長類型是能夠設置偏移量的一維標量。學習
1 let str = "Strengthen!" 2 //from，to，by 最後一個值是 >(或<) to的值 3 for num in stride(from: str.count-1,to: 0,by: -1) 4 { 5 let char:Character = str[str.index(str.startIndex,offsetBy: num)] 6 print("\(char) ", terminator: "") 7 } 8 //Prints "! n e h t g n e r t" 9 10 //from，through，by 最後一個值是 >=(或<=) through的值 11 for num in stride(from: str.count-1,through: 0,by: -1) 12 { 13 let char:Character = str[str.index(str.startIndex,offsetBy: num)] 14 print("\(char) ", terminator: "") 15 } 16 //Prints "! n e h t g n e r t S "
字符串轉字符數組：編碼
1 let str = "I am Strengthen" 2 let array = str.components(separatedBy:" ") 3 print("\(array) ", terminator: "") 4 //["I", "am", "Strengthen"]
字符數組轉字符串：url
1 /*字符數組轉字符串*/ 2 let arrayStr = ["s","t","r","e","n","g","t","h","e","n","!"] 3 4 //方式1 5 let str1 = arrayStr.joined(separator: "") 6 let str2 = arrayStr.joined(separator: "-") 7 print("\(str1) ", terminator: "") 8 print("\(str2) ", terminator: "") 9 //strengthen! 10 //s-t-r-e-n-g-t-h-e-n-! 11 12 //方式2：注意與方式1比較，方式2只在首位添加"-" 13 let str3 = arrayStr.reduce("", {$0 + $1}) 14 let str4 = arrayStr.reduce("-", {$0 + $1}) 15 print("\(str3) ", terminator: "") 16 print("\(str4) ", terminator: "") 17 //strengthen! 18 //-strengthen! 19 20 /*整數數組轉字符串*/ 21 let arrayInt = [0,1,2,3,4,5,6,7,8,9] 22 let dataInt = arrayInt.map(String.init) 23 let strInt = dataInt.joined(separator: "-") 24 print("\(strInt) ", terminator: "") 25 //0-1-2-3-4-5-6-7-8-9
最強字符串解析，你想知道，我都有！！！
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