Python中JSON字符串转JSON对象/类对象

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Python中JSON字符串转JSON对象/类对象

JSON字符串和JSON对象互转

字符串转对象

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import json

# 一些 JSON:
x =  '{ "name":"Bill", "age":63, "city":"Seatle"}'

# 解析 x:
y = json.loads(x)

# 结果是 Python 字典：
print(y["age"])

对象转字符串

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import json

# Python 对象（字典）：
x = {
  "name": "Bill",
  "age": 63,
  "city": "Seatle"
}

# 转换为 JSON：
y = json.dumps(x)

# 结果是 JSON 字符串：
print(y)

类型映射

当 Python 转换为 JSON时，Python 对象会被转换为 JSON（JavaScript）等效项：

Python JSON
dict Object
list Array
tuple Array
str String
int Number
float Number
True true
False false
None null

JSON和class转换

安装

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pip install pydantic

简单示例

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from datetime import datetime
from typing import List, Optional
from pydantic import BaseModel

class User(BaseModel):
    id: int
    name: str = 'John Doe'
    signup_ts: Optional[datetime] = None
    friends: List[int] = []

external_data = {'id': '123', 'signup_ts': '2017-06-01 12:22', 'friends': [1, '2', b'3']}
user = User(**external_data)
print(user)

树状数据

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import json
from typing import List, Optional

from pydantic import BaseModel


class TreeNode(BaseModel):
    name: str
    children: Optional[List['TreeNode']] = None


# 将 JSON 字符串解析为树状结构
json_str = '''
{
    "name": "root",
    "children": [
        {
            "name": "child1",
            "children": [
            ]
        },
        {
            "name": "child2",
            "children": []
        }
    ]
}
'''

# 使用 pydantic 解析 JSON
json_obj = json.loads(json_str)
tree = TreeNode(
    **json_obj
)

print(tree.name)  # 输出: root
print(tree.children[0].name)  # 输出: child1

# 将树状结构转换为 JSON 字符串
json_str = tree.model_dump_json(indent=4)
print(json_str)

列表数据

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import json
from pydantic import BaseModel

# 定义 Pydantic 模型
class User(BaseModel):
    name: str
    age: int

# JSON 字符串
json_string = '[{"name": "Alice", "age": 30}, {"name": "Bob", "age": 25}]'

# 解析 JSON 字符串
data = json.loads(json_string)

# 创建 Pydantic 对象
users = [User(**item) for item in data]

# 打印结果
for user in users:
    print(user)

转python中的dict

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obj.model_dump()

转JSON字符串

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json_str = obj.model_dump_json(indent=4)