Python Json读写操作_JsonPath用法详解
1. 介绍
jsonpath是一种信息抽取类库，是从json文档中抽取指定信息的工具，提供多种语言实现版本，包括javascript、python、php和java。
JSONPath的安装方法如下：pip install jsonpath
JSONPath语法和XPATH语法对比，JSON结构清晰，可读性高，复杂度低，非常容易匹配。JSONPath的语法与Xpath类似，如下表所示为JSONPath与XPath语法对比：
2. 代码示例
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
}
}
}变量bookJson中已经包含了这段JSON字符串，可通过以下代码反序列化得到JSON对象：
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books=json.loads(bookJson)
1）查看store下的bicycle的color属性：
checkurl = "$.store.bicycel.color" print(jsonpath.jsonpath(books, checkurl)) # 输出：['red']
2）输出book节点中包含的所有对象：
checkurl = "$.store.book[*]" object_list=jsonpath.jsonpath(books, checkurl) print(object_list)
3）输出book节点的第一个对象：
checkurl = "$.store.book[0]" obj = jsonpath.jsonpath(books, checkurl) print(obj) # 输出: ['category': 'reference', 'author': 'Nigel Rees', 'title': 'Sayings of the Century', 'price': 8.95}]
4）输出book节点中所有对象对应的属性title值：
checkurl = "$.store.book[*].title" titles = jsonpath.jsonpath(books, checkurl) print(titles) # 输出: ['Sayings of the Century', 'The Lord of the Rings']
5）输出book节点中category为fiction的所有对象：
checkurl = "$.store.book[?(@.category=='fiction')]”
books=jsonpath.jsonpath(books, checkurl)
print(books)
# 输出:[{'category': 'fiction', 'author': 'J. R. R. Tolkien', 'title': 'The Lordof the Rings', 'isbn': '0-395-19395-8'， 'price': 22.99}]6）输出book节点中所有价格小于10的对象：
checkurl="$.store.book[?(@.price<10)]"
books = jsonpath.jsonpath(books, checkurl)
print(books)
# 输出: [{'category': 'reference', 'author': 'Nigel Rees', 'title':'Sayings of the Century', 'price': 8.95}]7）输出book节点中所有含有isb的对象：
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}] 
