python  dataclass 快速创建数据类的方法

from dataclasses import dataclass, asdict
import json
@dataclass
class Address:
    street: str
    city: str
@dataclass
class User:
    name: str
    age: int
    email: str
    address: Address  # User 包含一个 Address 类型的属性

user = User(name="John Doe", age=30, email="john.doe@example.com",
            address=Address(street="123 Elm Street", city="Gotham"))
# 将数据类实例转换为字典，包括嵌套的数据类
user_dict = asdict(user)
# 将字典转换为JSON字符串
user_json = json.dumps(user_dict)
print(user_json)

from datetime import datetime
@dataclass
class User:
    name: str
    age: int
    email: str
    address: Address
    birthday: datetime  # 假设我们添加了一个 datetime 类型的属性
def datetime_converter(o):
    if isinstance(o, datetime):
        return o.__str__()
user = User(name="John Doe", age=30, email="john.doe@example.com",
            address=Address(street="123 Elm Street", city="Gotham"),
            birthday=datetime(1990, 1, 1))
user_dict = asdict(user)
# 使用 default 参数处理 datetime 对象
user_json = json.dumps(user_dict, default=datetime_converter)
print(user_json)

from dataclasses import dataclass, asdict, astuple, replace
@dataclass
class Point:
    x: int
    y: int
p = Point(10, 20)
print(p)  # 输出: Point(x=10, y=20)
p_dict = asdict(p)
print(p_dict)  # 输出: {'x': 10, 'y': 20}
p_tuple = astuple(p)
print(p_tuple)  # 输出: (10, 20)
p_new = replace(p, x=100)
print(p_new)  # 输出: Point(x=100, y=20)

from dataclasses import dataclass, field, fields
@dataclass
class Person:
    name: str
    age: int = field(default=18, metadata={"description": "Age of the person"})
    is_student: bool = False
# 获取Person数据类的字段信息
for f in fields(Person):
    print(f"name={f.name}, type={f.type}, default={f.default}, metadata={f.metadata}")
# 输出示例：
# name=name, type=<class 'str'>, default=<dataclasses._MISSING_TYPE object at 0x...>, metadata={}
# name=age, type=<class 'int'>, default=18, metadata={'description': 'Age of the person'}
# name=is_student, type=<class 'bool'>, default=False, metadata={}