import dataclasses
@dataclasses.dataclass
class User:
user_id: int
user_name: str
first_name: str
last_name: str
age: int = 0
def __post_init__(self):
self.full_name = f'{self.first_name} {self.last_name}'
u = User(1, 'admin', 'Jim', 'Green')
print(u)
# User(user_id=1, user_name='admin', first_name='Jim', last_name='Green', age=0)
print(u.full_name)
# Jim Green
u.full_name = 'Han Meimei'
print(u.full_name)
# Han Meimei
print(dataclasses.asdict(u))
# {'user_id': 1, 'user_name': 'admin', 'first_name': 'Jim', 'last_name': 'Green', 'age': 0}
print(dataclasses.astuple(u))
# (1, 'admin', 'Jim', 'Green', 0)
相当于:
class User:
def __init__(self, user_id: int, user_name: str, first_name: str, last_name: str, age: int = 0):
self.user_id = user_id
self.user_name = user_name
self.first_name = first_name
self.last_name = last_name
self.full_name = f'{self.first_name} {self.last_name}'
self.age = age
def __str__(self):
return f"{self.__class__.__name__}(user_id={self.user_id}, user_name='{self.user_name}', first_name='{self.first_name}', last_name='{self.last_name}, age={self.age}')"
def asdict(self):
return {
'user_id': self.user_id,
'user_name': self.user_name,
'first_name': self.first_name,
'last_name': self.last_name,
'age': self.age,
}
def astuple(self):
return self.user_id, self.user_name, self.first_name, self.last_name, self.age,
u = User(1, 'admin', 'Jim', 'Green')
print(u)
print(u.full_name)
u.full_name = 'Han Meimei'
print(u.full_name)
print(u.asdict())
print(u.astuple())
其他特性
@dataclasses.dataclass(*, init=True, repr=True, eq=True, order=False,
unsafe_hash=False, frozen=False, match_args=True, kw_only=False, slots=False,
weakref_slot=False)
init
是否生成__init__
方法(默认)repr
是否生成__repr__
方法(默认)eq
是否生成__eq__
方法(默认)order
是否生成__lt__
,__le__
,__gt__
,__ge__
方法unsafe_hash
是否生成__hash__
方法
能 hash 的是不会变化对象,否则会出问题,需要谨慎使用。frozen
是否允许对字段赋值match_args
kw_only
是否仅关键词传参slots
是否生成__slots__
方法weakref_slot
是否添加__wrakref__
槽位(弱引用)
指定 weakref_slot=True 而不同时指定 slots=True 将会导致错误。