Python Json讀寫操作之JsonPath怎麼使用

Python Json讀寫操作_JsonPath用法詳解

1. 介紹

JSONPath是一種資訊抽取類別庫，是從JSON文件中抽取指定資訊的工具，提供多種語言實作版本，包括Javascript、Python、PHP和Java。

JSONPath的安裝方法如下：pip install jsonpath

JSONPath語法和XPATH語法對比，JSON結構清晰，可讀性高，複雜度低，非常容易匹配。 JSONPath的語法與Xpath類似，如下表所示為JSONPath與XPath語法對比：

#2.程式碼範例

bookJson = {
  "store": {
    "book":[
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "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
    }
  }
}

變數bookJson中已經包含了這段JSON字串，可透過以下程式碼反序列化得到JSON物件：

books=json.loads(bookJson)

1）查看store下的bicycle的color屬性：

checkurl = "$.store.bicycel.color"
print(jsonpath.jsonpath(books, checkurl))
# 输出：['red']

2）輸出book節點中包含的所有物件：

checkurl = "$.store.book[*]"
object_list=jsonpath.jsonpath(books, checkurl)
print(object_list)

3）輸出book節點的第一個物件：

checkurl = "$.store.book[0]"
obj = jsonpath.jsonpath(books, checkurl)
print(obj)
# 输出: ['category': 'reference', 'author': 'Nigel Rees', 'title': 'Sayings of the Century', 'price': 8.95}]

4）輸出book節點中所有物件對應的屬性title值：

checkurl = "$.store.book[*].title"
titles = jsonpath.jsonpath(books, checkurl)
print(titles)
# 输出: ['Sayings of the Century', 'The Lord of the Rings']

5 ）輸出book節點中category為fiction的所有物件：

checkurl = "$.store.book[?(@.category=='fiction')]”
books=jsonpath.jsonpath(books, checkurl)
print(books)
# 输出:[{'category': 'fiction', 'author': 'J. R. R. Tolkien', 'title': 'The Lordof the Rings', 'isbn': '0-395-19395-8'， 'price': 22.99}]

6）輸出book節點中所有價格小於10的物件：

checkurl="$.store.book[?(@.price<10)]"
books = jsonpath.jsonpath(books, checkurl)
print(books)
# 输出: [{&#39;category&#39;: &#39;reference&#39;, &#39;author&#39;: &#39;Nigel Rees&#39;, &#39;title&#39;:&#39;Sayings of the Century&#39;, &#39;price&#39;: 8.95}]

7）輸出book節點中所有含有isb的對象：

checkurl = "$.store.book[?(@.isb)]"
books = jsonpath.jsonpath(books，checkurl)
print(books)
# 输出: [{'category': 'fiction', 'author': 'J. R. R. Tolkien', 'title': 'The Lord of the Rings', 'isbn': '0-395-19395-8'， 'price': 22.99}]

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