获取 JSON 对象内的 typeof 元素

Posted 2023-03-05

【中文标题】获取 JSON 对象内的 typeof 元素

【英文标题】：Get typeof element inside of JSON object

【发布时间】：2020-07-18 17:24:32

【问题描述】：

我有一个 JSON 文件，在 @Supercool 的帮助下，我能够获取每个文件的键名。我希望能够获得值的类型。

JSON 结构：

[
    
        "id": 1536700,
        "title": "final_output",
        "error": "",
        "data": [
            
                "metric": 4940616.0,
                "title": "d_revenue"
            ,
            
                "metric": 5132162.0,
                "title": "p_revenue"
            ,
            
                "metric": 4954576.0,
                "title": "s_revenue"
            ,
            
                "metric": 4882217.0,
                "title": "u_revenue"
            ,
            
                "metric": 4869609.0,
                "title": "t_revenue"
            ,
            
                "metric": 5075422.0,
                "title": "w_revenue"
            ,
            
                "metric": 4461996.0,
                "title": "v_revenue"
            
        ]
    
]

下一个结构：

[
    
        "run_id": 1536700,
        "code_title": "select_data",
        "error": "",
        "data": [
            
                "user_name": "C_51",
                "num1": 51,
                "num2": 101,
                "num3": 151
            ,
            
                "user_name": "H_51",
                "num1": 51,
                "num2": 101,
                "num3": 151
            ,
            
                "user_name": "C_52",
                "num1": 52,
                "num2": 102,
                "num3": 152
            ,
            
                "user_name": "H_52",
                "num1": 52,
                "num2": 102,
                "num3": 152
            ,
            
                "user_name": "C_53",
                "num1": 53,
                "num2": 103,
                "num3": 153
            
        ]
    
]

使用 Object.keys(yourObject) 获取密钥

 $.getJSON(api, function(elem) 
      let keys=elem.map( structure =>  Object.keys(structure.data[0]))         
   );

运行下面的sn-p来检查它是否有效

 let ele= ["id": 1536700,"title": "final_output","error": "",
"data": ["metric": 4940616.0,"title": "d_revenue","metric": 5132162.0,"title": "p_revenue","metric":4954576.0,"title": "s_revenue","metric": 4882217.0,"title":"u_revenue","metric": 4869609.0,"title":"t_revenue","metric": 5075422.0,"title": "w_revenue","metric": 4461996.0,"title": "v_revenue"
]
,
"run_id": 1536700,"code_title": "select_data","error": "",
  "data": ["user_name": "C_51","num1": 51,"num2": 101,"num3": 151,"user_name": "H_51","num1": 51,"num2": 101, "num3": 151,"user_name": "C_52","num1": 52,"num2": 102,"num3": 152,"user_name": "H_52","num1": 52,"num2": 102,"num3":152,"user_name": "C_53","num1": 53,"num2": 103,"num3": 153
]]
 console.log(ele.map( structure =>  Object.keys(structure.data[0])))
 console.log(ele.map( structure =>  Object.values(structure.data[0])))

.as-console-wrapper  max-height: 100% !important; top: 0; 

我希望能够获取每个值的类型。对于上面列出的值，我可以得到这个吗？

[
  [
    number,
    string
  ],
  [
    string,
    number,
    number,
    number
  ]
]

【问题讨论】：

保留密钥不是更有意义吗？

@RoboRobok，你是什么意思？

您可以将其转换为将值替换为类型的对象，而不是将其保存在数组中。虽然不确定你需要它做什么，但我几乎 100% 肯定你做了一些有趣的事情。

@Supercool 对象键在 javascript 中始终是字符串。

ele.map(structure => Object.values(structure.data[0]).map(v => typeof v))

【参考方案1】：

let ele = ["id": 1536700,"title": "final_output","error": "", "data": ["metric": 4940616.0,"title": "d_revenue","metric": 5132162.0,"title": "p_revenue","metric":4954576.0,"title": "s_revenue","metric": 4882217.0,"title":"u_revenue","metric": 4869609.0,"title":"t_revenue","metric": 5075422.0,"title": "w_revenue","metric": 4461996.0,"title": "v_revenue"], "run_id": 1536700,"code_title": "select_data","error": "", "data": ["user_name": "C_51","num1": 51,"num2": 101,"num3": 151,"user_name": "H_51","num1": 51,"num2": 101, "num3": 151,"user_name": "C_52","num1": 52,"num2": 102,"num3": 152,"user_name": "H_52","num1": 52,"num2": 102,"num3":152,"user_name": "C_53","num1": 53,"num2": 103,"num3": 153]];

console.log(ele.map(structure => Object.values(structure.data[0]).map(v => typeof v)));

【讨论】：

请记住，JavaScript 并不能保证每种情况下的对象属性顺序。

使用地图将保证它***.com/questions/5525795/…

@Supercool。 map 不保证财产顺序，它是对 Object.values() 的调用。

【参考方案2】：

通过 Object.values(obj) 做一个map() 并使用typeof 值返回类型

let ele= ["id": 1536700,"title": "final_output","error": "",
"data": ["metric": 4940616.0,"title": "d_revenue","metric": 5132162.0,"title": "p_revenue","metric":4954576.0,"title": "s_revenue","metric": 4882217.0,"title":"u_revenue","metric": 4869609.0,"title":"t_revenue","metric": 5075422.0,"title": "w_revenue","metric": 4461996.0,"title": "v_revenue"
]
,
"run_id": 1536700,"code_title": "select_data","error": "",
  "data": ["user_name": "C_51","num1": 51,"num2": 101,"num3": 151,"user_name": "H_51","num1": 51,"num2": 101, "num3": 151,"user_name": "C_52","num1": 52,"num2": 102,"num3": 152,"user_name": "H_52","num1": 52,"num2": 102,"num3":152,"user_name": "C_53","num1": 53,"num2": 103,"num3": 153
]]
console.log("Keys are ..");
 console.log(ele.map( structure =>  Object.keys(structure.data[0])))
console.log("and their correspondent value types are ..."); 
 console.log(ele.map( structure =>  Object.values(structure.data[0]).map(value => typeof value)))

.as-console-wrapper  max-height: 100% !important; top: 0; 

【参考方案3】：

Javascript 是一种原型语言，所以你可以在 js 中的任何结构上使用constructor.name 属性来查看它是什么类型。

简单示例：

const a =  t: 5, s: '', d: false, e:[], f:, d:5.53 ;
for (let k in a) 
  console.log(k,a[k].constructor.name);

【讨论】：

做了一个sn-p并添加了密钥，因为它没有按顺序登录

map会保证***.com/questions/5525795/…