Python JSON 基本操作

最新推荐文章于 2025-06-18 09:00:00 发布

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Python version ： 3.4.4

测试数据：

import json
aa = {"name": "kk", "age": 99 }
bb = [ {"name": "mm", "age": 10},{"name": "qq", "age": 20},{"name": "hh", "age": 50} ]

json模块提供的函数 json.dumps() 和 json.loads()

输出：

>>> print(bb)
[{'name': 'mm', 'age': 10}, {'name': 'qq', 'age': 20}, {'name': 'hh', 'age': 50}]
>>>
>>> data=json.dumps(bb)
>>> print(data)
[{"name": "mm", "age": 10}, {"name": "qq", "age": 20}, {"name": "hh", "age": 50}]
>>>
>>> load = json.loads(data)
>>> print(load)
[{'name': 'mm', 'age': 10}, {'name': 'qq', 'age': 20}, {'name': 'hh', 'age': 50}]
>>>

排序：

>>> data = json.dumps(bb,sort_keys=True)
>>> print(data)
[{"age": 10, "name": "mm"}, {"age": 20, "name": "qq"}, {"age": 50, "name": "hh"}]
>>>

格式化输出：

>>> data = json.dumps(bb,indent=4)
>>> print(data)
[
    {
        "name": "mm",
        "age": 10
    },
    {
        "name": "qq",
        "age": 20
    },
    {
        "name": "hh",
        "age": 50
    }
]
>>>

输出某行数据：

>>> print(bb[0])
{'name': 'mm', 'age': 10}
>>>
>>> print(bb[1])
{'name': 'qq', 'age': 20}
>>>
>>> print(bb[2])
{'name': 'hh', 'age': 50}
>>>

输出某行数据某个值：

>>> print(bb[1]["name"])
qq
>>>
>>> print(bb[1]["age"])
20
>>>

遍历/循环 JSON ：

>>> bb = [ {"name": "mm", "age": 10},{"name": "qq", "age": 20},{"name": "hh", "age": 50} ]
>>>
>>> for item in bb:
...     print(item,item["name"])
...
{'name': 'mm', 'age': 10} mm
{'name': 'qq', 'age': 20} qq
{'name': 'hh', 'age': 50} hh
>>>
>>> for i in range(len(bb)):
...     print(i,bb[i],bb[i]["name"])
...
0 {'name': 'mm', 'age': 10} mm
1 {'name': 'qq', 'age': 20} qq
2 {'name': 'hh', 'age': 50} hh
>>>
>>> for i,item in enumerate(bb):
...     print(i,item,item["name"])
...
0 {'name': 'mm', 'age': 10} mm
1 {'name': 'qq', 'age': 20} qq
2 {'name': 'hh', 'age': 50} hh
>>>
>>> for item in bb:
...     print("name=%s,age=%s,age=%f"%(item["name"],item["age"],item["age"]))
...
name=mm,age=10,age=10.000000
name=qq,age=20,age=20.000000
name=hh,age=50,age=50.000000
>>>
>>> for item in bb:
...     print("My name is {0} ".format(item["name"]))
...
My name is mm
My name is qq
My name is hh
>>>
>>> for i,j in bb:
...     print("name: {0}, age: {1}".format(i,j))
...
name: name, age: age
name: name, age: age
name: name, age: age
>>>

json 转 python 数据格式定义:

+---------------+-------------------+
| JSON          | Python            |
+===============+===================+
| object        | dict              |
+---------------+-------------------+
| array         | list              |
+---------------+-------------------+
| string        | str               |
+---------------+-------------------+
| number (int)  | int               |
+---------------+-------------------+
| number (real) | float             |
+---------------+-------------------+
| true          | True              |
+---------------+-------------------+
| false         | False             |
+---------------+-------------------+
| null          | None              |
+---------------+-------------------+

python 转 json 数据格式定义:

 +-------------------+---------------+
 | Python            | JSON          |
 +===================+===============+
 | dict              | object        |
 +-------------------+---------------+
 | list, tuple       | array         |
 +-------------------+---------------+
 | str               | string        |
 +-------------------+---------------+
 | int, float        | number        |
 +-------------------+---------------+
 | True              | true          |
 +-------------------+---------------+
 | False             | false         |
 +-------------------+---------------+
 | None              | null          |
 +-------------------+---------------+

更多参考：JSON encoder and decoder