python之json操作

1.json.dumps()用于将dict类型的数据转成str

备注：文件路径前面加上 r 是为了避免转义

 1 import json
 2 
 3 dict = {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
 4 string = json.dumps(dict)
 5 print(dict)
 6 print(string)
 7 print(type(dict))
 8 print(type(string))
 9 
10 with open(r'C:UserszyDocumentsGitHubpython3searchTestjson.json','w')as f:
11     f.write(string)

1 {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
2 {"a": "wo", "b": "zai", "c": "zhe", "d": "li"}
3 <class 'dict'>
4 <class 'str'>

如果没有进行转换，则会报错：TypeError: write() argument must be str, not dict

1 import json
2 
3 dict = {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
4 with open(r'C:UserszyDocumentsGitHubpython3searchTestjson.json','w')as f:
5     f.write(dict)

1 {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
2 Traceback (most recent call last):
3 <class 'dict'>
4   File "C:/Users/zy/Documents/GitHub/python3/searchTest/json_test.py", line 11, in <module>
5     f.write(dict)
6 TypeError: write() argument must be str, not dict

 json.dumps()参数解释：常用参数解释

indent：应该是一个非负的整型，如果是0，或者为空，则一行显示数据；否则会换行且按照indent的数量显示前面的空白

sort_keys：将数据根据keys的值进行排序

1 response = requests.post(url=url,headers=headers).json()
2 print(json.dumps(response,sort_keys=True,indent=4))

举例结果：

 1 {
 2     "code": "200",
 3     "message": "",
 4     "redirect": "",
 5     "value": {
 6         "name": "so",
 7         "title": "360",
 8         "value": "2"
 9     }
10 }

2.json.loads():用于将str类型的数据转成dict

 1 dict = {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
 2 dumps = json.dumps(dict)
 3 loads = json.loads(dumps)
 4 
 5 print(dict)
 6 print(dumps)
 7 print(loads)
 8 
 9 print(type(dict))
10 print(type(dumps))
11 print(type(loads))

1 {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
2 {"a": "wo", "b": "zai", "c": "zhe", "d": "li"}
3 {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
4 <class 'dict'>
5 <class 'str'>
6 <class 'dict'>

3.json.dump()用于将dict类型的数据转成str，并写入到json文件中

1 dict = {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
2 json.dump(dict,open(r'C:UserszyDocumentsGitHubpython3searchTestjson.json','w'))

4.json.load()用于从json文件中读取数据

1 filename = (r'C:UserszyDocumentsGitHubpython3searchTestjson.json')
2 jsObj = json.load(open(filename))
3 print(jsObj)
4 print(type(jsObj))

1 {'a': 'wo', 'b': 'zai', 'c': 'zhe', 'd': 'li'}
2 <class 'dict'>

常见问题:

　　1. json.dumps方法默认会输出成这种格式"u535au5ba2u56ed"

　　要输出中文需要指定ensure_ascii参数为False，如下代码片段：

　　json.dumps({'text':"中文"},ensure_ascii=False,indent=2) # indent 进行缩进展示