如何根据键的过滤器获取 json 路径？

Question

我有一个 json，我必须 select 来自 json 对象的作者姓名，该对象不包含 available 作为键入它

{
"store": {
"book": [
    {
        "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
    },
    {
        "category": "fiction",
        "author": "Evelyn Waugh",
        "title": "Sword of Honour",
        "price": 12.99
        "available":false
    },
    {
        "category": "fiction",
        "author": "Herman Melville",
        "title": "Moby Dick",
        "isbn": "0-553-21311-3",
        "price": 8.99
    },
    {
        "category": "fiction",
        "author": "J. R. R. Tolkien",
        "title": "The Lord of the Rings",
        "isbn": "0-395-19395-8",
        "price": 22.99
    }
],
"bicycle": {
    "color": "red",
    "price": 19.95
}
},
"expensive": 10
}

所以如果可以使用 jsonpath 是否可以，我该如何实现？

Answer 1

您可以过滤没有属性 'available' 的书，然后通过过滤得到作者姓名

const books = [
  {
    category: 'reference',
    author: 'Nigel Rees',
    title: 'Sayings of the Century',
    price: 8.95
  },
  {
    category: 'fiction',
    author: 'Evelyn Waugh',
    title: 'Sword of Honour',
    price: 12.99,
    available: false
  },
  {
    category: 'fiction',
    author: 'Herman Melville',
    title: 'Moby Dick',
    isbn: '0-553-21311-3',
    price: 8.99
  },
  {
    category: 'fiction',
    author: 'J. R. R. Tolkien',
    title: 'The Lord of the Rings',
    isbn: '0-395-19395-8',
    price: 22.99
  }
]

const authorNames = books
  .filter(book => !book.hasOwnProperty('available'))
  .map(book => book.author)

console.log(authorNames)

参考

Object.prototype.hasOwnProperty()

Answer 2

我认为您需要可以为您完成任务的 JSONpath，因此您可以试试这个。

$..book[?(!@.available)].author

试穿 https://jsonpath.com/它的工作方式和你想要的一样

Answer 3

您可以使用 for..in 构造来遍历对象的任意属性：

for (var key in obj.d) {
console.log("Key: " + key);
console.log("Value: " + obj.d[key]);}

或者像这样检查您的可用密钥，例如

            var Data_Array = {
"Private": {
    "Price": {
        "Adult": "18",
        "Child": [{
            "FromAge": "0",
            "ToAge": "12",
            "Price": "10"
        }]
    }
}};var child = 'Child' in Data_Array.Private.Price && Data_Array.Private.Price.Child[0] || 'there is no child';console.log(child);

这会告诉你是否有可用的密钥，然后像这样获取作者姓名，一个例子

通过使用单词“b”，您仍在使用键名。

    var info = {"fname": "A","lname": "B","Age": "34","favcolor": {"color1":"Gray", "color2":"Black", "color3":"Blue"}};

请看下面的代码片段。

for(key in info) {var infoJSON = info[key];console.log(infoJSON);}

如何根据键的过滤器获取 json 路径？

How to get the json path based on filter on the key?

javascript

json

jsonpath

参考