Swift_字符串详解(String)
类型别名
//类型别名fileprivate func testTypeAliases() { let index = String.Index.self print("\(index)") let utf8index = String.UTF8Index.self print("\(utf8index)") let utf16index = String.UTF16Index.self print("\(utf16index)") let unicodeScalarIndex = String.UnicodeScalarIndex.self print("\(unicodeScalarIndex)") let greeting = "XuBaoAiChiYu" print(greeting[greeting.startIndex])//输出字符串的第一个字符 print(greeting[greeting.characters.index(before: greeting.endIndex)])//输出字符串的最后一个字符 print(greeting[greeting.characters.index(after: greeting.startIndex)])//输出字符串的第二个字符 print(greeting[greeting.characters.index(greeting.startIndex, offsetBy: 7)])//输出字符串的第八个字符 /* print Index Index Index Index X u u C */} 初始化
//初始化fileprivate func testInitializers() { //初始化 var string: String = String() string = "XuBaoAiChiYu" print(string) //char 初始化 let char: Character = "X" string = String(char) print(string) string = String.init(char) print(string) string = "\(char)" print(string) // 通过CharacterView let charView: String.CharacterView = String.CharacterView("XuBaoAiChiYu") string = String(charView) print(string) //通过 utf-16 编码 let utf16: String.UTF16View = string.utf16 string = String(describing: utf16) print(utf16) //通过 utf-8 编码 let utf8: String.UTF8View = string.utf8 string = String(describing: utf8) print(utf8) //通过多个字符串组合生成 string = String(stringInterpolation: "xu", "bao") print(string) //char初始化 连续count次 string = String(repeating: String(char), count: 6) print(string) //通过其他常用数据初始化 string = String(stringInterpolationSegment: true) print(string) string = String(stringInterpolationSegment: 24) print(string) // 通过NSString初始化,不推荐 string = NSString(string: "XuBaoAiChiYu") as String print(string) string = NSString.init(string: "XuBaoAiChiYu") as String print(string) // 组合生成 string = NSString(format: "%@", "XuBaoAiChiYu") as String print(string) /* print XuBaoAiChiYu X X X XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu xubao XXXXXX true 24 XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu */} 文件路径操作
//文件路径操作fileprivate func testWorkingWithPaths() { var path = "xubaoaichiyu/ios/swift" print(path) //路径分割成熟数组 var pathComponents = (path as NSString).pathComponents print(pathComponents) //数组组合成路径 path = NSString.path(withComponents: pathComponents) print(path) //Document目录 let documents: [String] = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, .userDomainMask, true) print(documents) let documentPath: String = documents.first! print(documentPath) //寻找文件夹下包含多少个路径 var complete = documentPath.completePath(caseSensitive: true) print(complete) //寻找文件夹下包含指定扩展名的文件路径个数 var outName = "" let filterTypes = ["txt", "plist"] complete = documentPath.completePath(into: &outName, caseSensitive: true, matchesInto: &pathComponents, filterTypes: filterTypes) print("completePathIntoString:\(complete)") //添加路径 path = (documentPath as NSString).appendingPathComponent("test") print(path) //添加扩展 path = (path as NSString).appendingPathExtension("plist")! print(path) print("是否绝对路径:\((path as NSString).isAbsolutePath)") print("最后一个路径名:\((path as NSString).lastPathComponent)") print("扩展名:\((path as NSString).pathExtension)") //去掉扩展名 var tempPath = (path as NSString).deletingPathExtension print(tempPath) //去掉最后一个路径 tempPath = (path as NSString).deletingLastPathComponent print(tempPath) //转%格式码 let allowedCharacters:CharacterSet = CharacterSet.controlCharacters tempPath = path.addingPercentEncoding(withAllowedCharacters: allowedCharacters)! print(tempPath) //转可见 tempPath = (tempPath as NSString).removingPercentEncoding! print(tempPath) /* print xubaoaichiyu/ios/swift ["xubaoaichiyu", "ios", "swift"] xubaoaichiyu/ios/swift ["/Users/caoxu/Documents"] /Users/caoxu/Documents 4 completePathIntoString:1 /Users/caoxu/Documents/test /Users/caoxu/Documents/test.plist 是否绝对路径:true 最后一个路径名:test.plist 扩展名:plist /Users/caoxu/Documents/test /Users/caoxu/Documents %2F%55%73%65%72%73%2F%63%61%6F%78%75%2F%44%6F%63%75%6D%65%6E%74%73%2F%74%65%73%74%2E%70%6C%69%73%74 /Users/caoxu/Documents/test.plist */ } 文件读写操作
//文件读写操作fileprivate func testFile() { var string = "XuBaoAiChiYu" //Document目录 let documents = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true) var path = documents.first! path = (path as NSString).appendingPathComponent("xubaoaichiyu") path = (path as NSString).appendingPathExtension("text")! let pathUrl = URL(fileURLWithPath: path) do { //写入 try string.write(toFile: path, atomically: true, encoding: String.Encoding.utf8) try string.write(to: pathUrl, atomically: true, encoding: String.Encoding.utf8) // 读取 // 自动解析 try string = String(contentsOfFile: path) print(string) // 指定编码解析 try string = String(contentsOfFile: path, encoding: String.Encoding.utf8) print(string) // 使用默认的编码解析 如果不能解析 采取默认解析并返回解析编码 var encoding:String.Encoding = String.Encoding.utf16LittleEndian try string = String(contentsOfFile: path, usedEncoding: &encoding) print(string) // URl 读取 try string = String(contentsOf: pathUrl) print(string) try string = String(contentsOf: pathUrl, encoding: String.Encoding.utf8) print(string) try string = String(contentsOf: pathUrl, usedEncoding: &encoding) print(string) } catch { print("错误:\(error)") } /* print XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu XuBaoAiChiYu */} 获取字符串的Swift属性
//获取字符串的Swift属性fileprivate func testGettingProperties() { let string = String(stringInterpolation: "XuBaoAiChiYu", "QQ", "1045214799") // String.CharacterView print("String.CharacterView:\(string.characters)") // String.UnicodeScalarView print("String.UnicodeScalarView:\(string.unicodeScalars)") // String.UTF16View print("String.UTF16View:\(string.utf16)") // String.UTF8View print("String.UTF8View:\(string.utf8)") // hash值 print("hashValue:\(string.hashValue)") // 是否为空 print("isEmpty:\(string.isEmpty)") /* print String.CharacterView:CharacterView(_core: Swift._StringCore(_baseAddress: Optional(0x0000000100b06e80), _countAndFlags: 24, _owner: Optional(Swift._HeapBufferStorage ))) String.UnicodeScalarView:XuBaoAiChiYuQQ1045214799 String.UTF16View:XuBaoAiChiYuQQ1045214799 String.UTF8View:XuBaoAiChiYuQQ1045214799 hashValue:-8659559252040524018 isEmpty:false */} 获取字符串长度
//获取字符串长度fileprivate func testGettingLength() { var string: String = String() string = "XuBaoAiChiYu: 1045214799" // 起始位置 var index = string.startIndex print(index) // 结束位置 index = string.endIndex print(index) // NSString方式获取长度 var length = (string as NSString).length print(length) // swift方式获取 length = string.characters.distance(from: string.startIndex, to: string.endIndex) print(length) // 通过编码获取长度 length = string.lengthOfBytes(using: String.Encoding.utf8) print(length) /* print Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1) Index(_base: Swift.String.UnicodeScalarView.Index(_position: 24), _countUTF16: 0) 24 24 24 */} 大小写变化
//大小写变化fileprivate func testChangingCase() { var string = "XuBaoAiChiYu QQ 1045214799" print(string) //大写 string = string.uppercased() print(string) //小写 string = string.lowercased() print(string) /* print XuBaoAiChiYu QQ 1045214799 XUBAOAICHIYU QQ 1045214799 xubaoaichiyu qq 1045214799 */ } 字符串转数值
//字符串转数值fileprivate func testGettingNumericValues() { let string = "24" print(string) let nStr = string as NSString // 借用NSString输出 print(nStr) print("doubleValue:\(nStr.doubleValue)") print("floatValue:\(nStr.floatValue)") print("intValue:\(nStr.intValue)") print("integerValue:\(nStr.integerValue)") print("longLongValue:\(nStr.longLongValue)") print("boolValue:\(nStr.boolValue)") /* print 24 24 doubleValue:24.0 floatValue:24.0 intValue:24 integerValue:24 longLongValue:24 boolValue:true */} 增加字符串
//增加字符串fileprivate func testCombiningStrings() { var string = "XuBaoAiChiYu QQ 1045214799" print(string) // 添加字符串 string.append("_Swift") print(string) string += "_Swift" print(string) string.write("_Swift") print(string) // string后增加字符串并生成一个新的字符串 string = string + string print(string) // string后增加组合字符串并生成一个新的字符串 string = string.appendingFormat("_%@", "OC") print(string) // string后增加循环字符串，stringByPaddingToLength：完毕后截取的长度；startingAtIndex：从增加的字符串第几位开始循环增加。 string = string.padding(toLength: 30, withPad:"_Swift", startingAt:3) print(string) // 指定位置插入Character string.insert("5", at: string.characters.index(string.endIndex, offsetBy: -1)) print(string) // 指定位置插入字符串 string.insert(contentsOf: "78".characters, at: string.characters.index(string.startIndex, offsetBy: 9)) print(string) /* print XuBaoAiChiYu QQ 1045214799 XuBaoAiChiYu QQ 1045214799_Swift XuBaoAiChiYu QQ 1045214799_Swift_Swift XuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift XuBaoAiChiYu QQ 1045214799_Swift_Swift_SwiftXuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift XuBaoAiChiYu QQ 1045214799_Swift_Swift_SwiftXuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift_OC XuBaoAiChiYu QQ 1045214799_Swi XuBaoAiChiYu QQ 1045214799_Sw5i XuBaoAiCh78iYu QQ 1045214799_Sw5i */} 分割字符串
//分割字符串fileprivate func testDividingStrings() { let str = "XuBaoAiChiYu_QQ_1045214799" //根据指定的字符串分割成数组 var array = str.components(separatedBy: "_") print(array) //通过系统自带的分割方式分割字符串 array = str.components(separatedBy: CharacterSet.lowercaseLetters) print(array) // 指定位置后的字符串 var tempStr = str.substring(from: str.characters.index(str.startIndex, offsetBy: 3)) print(tempStr) // 指定位置前的字符串 tempStr = str.substring(to: str.characters.index(str.startIndex, offsetBy: 3)) print(tempStr) // 指定范围的字符串 let range = str.characters.index(str.endIndex, offsetBy: -6).. 查找字符串
//查找字符串fileprivate func testFindingStrings() { let str = "XuBaoAiChiYu_QQ_1045214799"; let searchRange = str.startIndex ..< str.characters.index(str.startIndex, offsetBy: 10) print(searchRange) //根据NSCharacterSet查找 let cSet = CharacterSet.uppercaseLetters var range = str.rangeOfCharacter(from: cSet) print(range!) //根据字符串查找 range = str.range(of: "Yu") print(range!) range = str.range(of: "Yu", options: NSString.CompareOptions.caseInsensitive, range: searchRange, locale: nil) if let tempRange = range { print("tempRange:\(tempRange)") } //block 行查找 str.enumerateLines { (line, stop) -> () in print(line) if "Yu" == line { stop = true } } //block查找 可设置查找方式 并得到找到的位置 str.enumerateSubstrings(in: searchRange, options: NSString.EnumerationOptions.byComposedCharacterSequences) { (substring, substringRange, enclosingRange, stop) -> () in print(substring!) if "A" == substring { print(substringRange) stop = true } } /* print Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1).. 替换字符串
//替换字符串fileprivate func testReplacingSubstrings() { var string = "XuBaoAiChiYu_QQ_1045214799" let replacingRange = string.startIndex.. 删除字符串
//删除字符串fileprivate func testRemovingSubstrings() { var string = "XuBaoAiChiYu_QQ_1045214799" print(string) //删除指定位置的字符串 string.remove(at: string.characters.index(string.startIndex, offsetBy: 1)) print(string) //根据范围删除字符串 let range = string.characters.index(string.endIndex, offsetBy: -6).. 比较字符串
//比较字符串fileprivate func testComparingStrings() { var string = "XuBaoAiChiYu_QQ_1045214799" let compareStr = "XuBaoAiChiYu_QQ_1045214799" let searchRange = string.characters.index(string.startIndex, offsetBy: 5)..