Swift_字符串详解(String)

时间：2022-12-18 05:04:09

Swift_字符串详解(String)

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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<Swift._StringBufferIVars, Swift.UInt16>)))

     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)..<str.endIndex

    tempStr = str.substring(with: range)

    print(tempStr)

    /*  print

     ["XuBaoAiChiYu", "QQ", "1045214799"]

     ["X", "B", "", "A", "C", "", "Y", "_QQ_1045214799"]

     aoAiChiYu_QQ_1045214799

     XuB

     214799

     */

}

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)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 10), _countUTF16: 1)

     Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 1), _countUTF16: 1)

     Index(_base: Swift.String.UnicodeScalarView.Index(_position: 10), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 12), _countUTF16: 1)

     XuBaoAiChiYu_QQ_1045214799

     X

     u

     B

     a

     o

     A

     Index(_base: Swift.String.UnicodeScalarView.Index(_position: 5), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 6), _countUTF16: 1)

     */

}

替换字符串

//替换字符串

fileprivate func testReplacingSubstrings() {

    var string = "XuBaoAiChiYu_QQ_1045214799"

    let replacingRange = string.startIndex..<string.characters.index(string.startIndex, offsetBy: 20)

    print(string)

    //全局替换

    string = string.replacingOccurrences(of: "+", with: " ")

    print(string)

    //设置替换的模式 并设置范围

    string = string.replacingOccurrences(of: "+", with: "_", options: NSString.CompareOptions.caseInsensitive, range: replacingRange)

    print(string)

    //将指定范围的字符串替换为指定的字符串

    string.replaceSubrange(replacingRange, with: "YYYYYYYYYYYYYYY")

    print(string)

    string = string.replacingCharacters(in: replacingRange, with: "YYYYY")

    print(string)

    /*  print

     XuBaoAiChiYu_QQ_1045214799

     XuBaoAiChiYu_QQ_1045214799

     XuBaoAiChiYu_QQ_1045214799

     YYYYYYYYYYYYYYY214799

     YYYYY9

     */

}

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)..<string.endIndex

    string.removeSubrange(range)

    print(string)

    //删除所有

    string.removeAll()

    string.removeAll(keepingCapacity: true)

    /*  print

     XuBaoAiChiYu_QQ_1045214799

     XBaoAiChiYu_QQ_1045214799

     XBaoAiChiYu_QQ_1045

     */

}

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)..<string.characters.index(before: string.endIndex)

    print(searchRange)

    //前缀

    var isHas = string.hasPrefix("Xu")

    print("hasPrefix:\(isHas)")

    //后缀

    isHas = string.hasSuffix("1045214799")

    print("hasSuffix:\(isHas)")

    //全比较是否相同

    isHas = string == compareStr

    print(isHas)

    //比较大小

    var result = string.compare(compareStr)

    print(result.hashValue)

    //添加比较范围

    result = string.compare(compareStr, options: NSString.CompareOptions.caseInsensitive, range: searchRange, locale: nil)

    print("result:\(result.hashValue)")

    // 返回两个字符串相同的前缀

    string = string.commonPrefix(with: compareStr, options: NSString.CompareOptions.caseInsensitive)

    print(string)

    /* print

     Index(_base: Swift.String.UnicodeScalarView.Index(_position: 5), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 25), _countUTF16: 1)

     hasPrefix:true

     hasSuffix:true

     true

     1

     result:0

     XuBaoAiChiYu_QQ_1045214799

     */

}

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