Swift学习系列 字典的使用

字典的概念

字典的概念

字典的初始化


    //字典的定义  
    let dic:[String:Any] = ["名称":"liuxh","年龄":18]
    print(dic)
        

字典元素的基本操作

字典元素的基本操作.png

  //增
    var dict:[String:Any] = ["名称":"liuxh","年龄":18]
        
    dict["性别"] = "男"
        
    print(dict)
    //改
    dict.updateValue("汉", forKey: "民族")
        
    //["Key"] updateValue  直接修改数值 如果没有发现相应的key 增加键值对  如果发现有相应的key  做修改操作
        
    //删除
    dict.removeAll()//删除所有
        
    dict.removeValue(forKey:"性别")//删除 某个键值对
    print(dict)
    //按索引删除
        
    let index = dict.index(forKey: "民族")
    dict.remove(at: index!)
        
    print(dict)

字典的基本操作

字典的基本操作.png

• 字典的遍历

 //获取所有的key
        
    let  keys = dict.keys
        
    print (keys)
    //获取所有的value
    let values = dict.values
    print (values)
    //遍历所有的value
    for value in values {
            
    print(value)
            
    }
    //遍历所有的key
        
    for key in keys {
                 
    print(key)
    }
        
    //遍历字典键值对

    for (key,value) in dict {
    print(key,":",value)
    }
    

• 字典合并

        //字典合并
        
    let dict2:[String:Any] = ["c":3]
        
    //吧dic2 里面所有的键值对 添加到dict
    for (key,value) in dict2 {
     dict[key]=value
    }
        

     
      //方法二  添加扩展
     
        let dict3:[String:Any] = Dictionary<String, Any>.addResultDict(dict: dict, dic2: dict2)
        print(dict3)
        
        //两个字典相加
        let d1:[String:Any] = ["a":1]
        let d2:[String:Any] = ["b":2]
        let d3 = Dictionary.addResultDict(dict: d1, dic2: d2)
        print(d3)
    
    
extension Dictionary{
    static func addResultDict(dict:Dictionary,dic2:Dictionary) -> Dictionary{
    
        var result = dict
        
        for (key,value) in dic2 {
            result[key]=value
        }
        
        return result
        
    }
         
}