Python3: json 模块 - JSON 的编码和解析

一时失言乱红尘 2021-09-21 23:06 390阅读 0赞

本文链接: [https://blog.csdn.net/xietansheng/article/details/115559110][https_blog.csdn.net_xietansheng_article_details_115559110]

[Python3 学习笔记（目录）][Python3]

Python Docs: [json — JSON encoder and decoder][json _ JSON encoder and decoder]

`json`模块用于对 JSON 的编码和解码。

`json`模块对 JSON 进行编码和解码时，JSON 字符串和 Python 对象之间的转换关系:

Decoder
    -------------------------------------------
    JSON String        -->        Python Object
    -------------------------------------------
    object              |         dict
    array               |         list
    string              |         str
    number(int)         |         int
    number(real)        |         float
    true/false          |         True/False
    null                |         None
    -------------------------------------------
    
                     Encoder
    -------------------------------------------
    Python Object      -->        JSON String
    -------------------------------------------
    dict                |         object
    list, tuple         |         array
    str                 |         string
    int, float          |         number
    True/False          |         true/false
    None                |         null
    -------------------------------------------

`json`模块对 JSON 进行编码和解码主要使用下面两个方法:

# 编码: Python Object --> JSON String
    json.dumps(obj, *, skipkeys=False, ensure_ascii=True, 
               check_circular=True, allow_nan=True, 
               cls=None, indent=None, separators=None,
               default=None, sort_keys=False, **kw)
    
    # 解码: JSON String --> Python Object
    json.loads(s, *, encoding=None, cls=None, object_hook=None, 
               parse_float=None, parse_int=None, parse_constant=None, 
               object_pairs_hook=None, **kw)

JSON 编码/解码代码示例:

import json
    
    # Python 对象
    py_obj = { 
        "key_int": 123,
        "key_float": 3.14,
        "key_bool": True,
        "key_str": "hello",
        "key_None": None,
        "key_list": ["abc", 123, 3.14, True],
        "key_tuple": ("abc", 123, 3.14, True),
        "key_dict": { 
            "aa": 123,
            "bb": "hello"
        }
    }
    
    # 编码, 返回 JSON 字符串
    json_str = json.dumps(py_obj)
    print(json_str)
    
    # 解码, 返回 Python 对象
    py_obj = json.loads(json_str)
    print(py_obj)
    
    
    # 编码后的 json_str 字符串值如下:
    """ { "key_int": 123, "key_float": 3.14, "key_bool": true, "key_str": "hello", "key_None": null, "key_list": ["abc", 123, 3.14, true], "key_tuple": ["abc", 123, 3.14, true], "key_dict": { "aa": 123, "bb": "hello" } } """
    
    # 解码后的 py_obj 对象值如下:
    """ { 'key_int': 123, 'key_float': 3.14, 'key_bool': True, 'key_str': 'hello', 'key_None': None, 'key_list': ['abc', 123, 3.14, True], 'key_tuple': ['abc', 123, 3.14, True], 'key_dict': { 'aa': 123, 'bb': 'hello' } } """

编码 JSON 时，格式化输出:

>>> import json
    >>> 
    >>> py_obj = { "key_int": 123, "key_str": "hello", "key_list": [123, 456]}
    >>> 
    >>> json.dumps(py_obj, indent=4)            # JSON 字符串缩进 4 个空格
    """ { "key_int": 123, "key_str": "hello", "key_list": [ 123, 456 ] } """

[https_blog.csdn.net_xietansheng_article_details_115559110]: https://blog.csdn.net/xietansheng/article/details/115559110
[Python3]: https://blog.csdn.net/xietansheng/article/details/109266600
[json _ JSON encoder and decoder]: https://docs.python.org/zh-cn/3/library/json.html