Swift_字典详解

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初始化

fileprivate func testInit() {    //空字典    var dic = [String:String]()    print(dic)        dic = [:]    print(dic)        dic = Dictionary()    print(dic)        dic = Dictionary
    
     ()    print(dic)        //非空字典    dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        dic = Dictionary(dictionaryLiteral: ("name","XuBaoAiChiYu"),("QQ","1045214799"))    print(dic)        /*  print          [:]     [:]     [:]     [:]     ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     ["name": "XuBaoAiChiYu", "QQ": "1045214799"]          */}
    

相关属性

//相关属性fileprivate func testProperties() {        let dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        print("count:\(dic.count)") // 有多个对元素    print("isEmpty:\(dic.isEmpty)") // 是否为空        // 获取所有key    let keys = [String](dic.keys)    print("keys:\(keys)")        // 获取所有value    let values = [String](dic.values)    print("values:\(values)")        print("startIndex:\(dic.startIndex)") // 首脚标    print("endIndex:\(dic.endIndex)")     // 尾脚标        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     count:2     isEmpty:false     keys:["name", "QQ"]     values:["XuBaoAiChiYu", "1045214799"]     startIndex:DictionaryIndex
    
     (_value: Swift.DictionaryIndexRepresentation
     
      ._native(Swift._NativeDictionaryIndex
      
       (nativeStorage: , offset: 1)))     endIndex:DictionaryIndex
       
        (_value: Swift.DictionaryIndexRepresentation
        
         ._native(Swift._NativeDictionaryIndex
         
          (nativeStorage: , offset: 4))) */}
         
        
       
      
     
    

查找元素

//查找元素fileprivate func testFindingObjects() {    let dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        if let dicIndex = dic.index(forKey: "name") { // 获取位置        let item = dic[dicIndex] // 根据位置获取键值对        print("key:\(item.0);value:\(item.1)")    }        let value = dic["name"] // 根据key提取Value    print("value:\(value)")        // 遍历输出    for (key, value) in dic {        print("\(key): \(value)")    }        // 所有key输出    for key in dic.keys {        print("key:\(key)")    }        // 所有value输出    for value in dic.values {        print("value: \(value)")    }        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     key:name;value:XuBaoAiChiYu     value:Optional("XuBaoAiChiYu")     name: XuBaoAiChiYu     QQ: 1045214799     key:name     key:QQ     value: XuBaoAiChiYu     value: 1045214799          */}

增加元素

//增加元素fileprivate func testAdd() {    var dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        // 如果没有则添加，有则修改    dic["language"] = "swift"    print(dic)        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     ["language": "swift", "name": "XuBaoAiChiYu", "QQ": "1045214799"]          */}

删除元素

//删除元素fileprivate func testRemove() {    var dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        let oldValue = dic.removeValue(forKey: "name")// 根据key删除,并返回删除的value    print("\(oldValue)")        // 先找到位置，然后根据位置删除    if let dictIndex = dic.index(forKey: "QQ") {        let oldItem = dic.remove(at: dictIndex)// 返回删除的元素对        print("key:\(oldItem.0);value:\(oldItem.1)")    }        dic.removeAll() // 删除所有元素    print(dic)        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     Optional("XuBaoAiChiYu")     key:QQ;value:1045214799     [:]          */}

修改元素

//修改元素fileprivate func testReplace() {    var dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        // 如果没有则添加，有则修改    dic["name"] = "XUBAO" // 修改    print(dic)        let oldValue = dic.updateValue("XUBAOAICHIYU", forKey: "name") // 修改，并返回原来的value    print("\(oldValue)")        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     ["name": "XUBAO", "QQ": "1045214799"]     Optional("XUBAO")          */}

排序

//排序fileprivate func testSort() {    let dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]    print(dic)        // 排序主要只排序key或者value,然后借用Array的排序    // 排序key    var array = dic.keys.sorted(by: { str1,str2 in str1 < str2 })    array = dic.keys.sorted(by: <)    print(array)        // 排序value    array = dic.values.sorted(by: {$0 > $1})    print(array)        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     ["QQ", "name"]     ["XuBaoAiChiYu", "1045214799"]          */}

文件读写

fileprivate func testReadingAndWriting() {    // Document目录    let documents:[String] = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)    let docDirPath = documents.first!    let path = (docDirPath as NSString).appendingPathComponent("test.plist")    let url = URL(fileURLWithPath: path)    var dic = ["name":"XuBaoAiChiYu","QQ":"1045214799"]        // 写    (dic as NSDictionary).write(toFile: path, atomically: true)    (dic as NSDictionary).write(to: url, atomically: true)        // 读    dic = NSDictionary(contentsOfFile: path) as! Dictionary    print(dic)    dic = NSDictionary(contentsOf: url) as! Dictionary    print(dic)        /*  print          ["name": "XuBaoAiChiYu", "QQ": "1045214799"]     ["name": "XuBaoAiChiYu", "QQ": "1045214799"]          */}