减少代码量, a data class requires a minimal amount of code
可以进行比较， 因为实现了 __eq__ , you can compare data classes because __eq__ is implemented for you
基于 对象属性 self.attr == other.attr
debugging 的时候可以打印详细的信息, 因为实现了__repr__, you can easily print a data class for debugging because __repr__ is implemented as well
进行了类型hint，减少数据类型bug， data classes require type hints, reduced the chances of bugs
dataclass介绍 实例(dataclass 类对象去重–有hash方法)
适合存储数据对象
1 存储数据并表示某种数据类型
2 对象进行比较
from dataclasses import dataclass
class Number:
def __init__(self, val):
self.val = val
one = Number(1)
print(one.val)
@dataclass()
class NewNumber:
val:int=0
new_one = Number(1)
print(new_one.val)
创建不可变对象 frozen=True
from dataclasses import dataclass
@dataclass(frozen=True)
class NewNumber:
val:int=0
a = NewNumber()
print(a.val)
a.val = 0
使用__post_init__进行初始化后处理
import math
class Float:
def __init__(self, val=0):
self.val = val
self._post_init()
def _post_init(self):
self.decimal, self.integer = math.modf(self.val)
f = Float(2.5)
print(f.decimal)
print(f.integer)
from dataclasses import dataclass
import math
@dataclass
class NewFloat:
val: float = 0.0
def __post_init__(self):
self.decimal,\
self.integer = math.modf(self.val)
nf = NewFloat(2.5)
print(nf.val)
print(nf.decimal)
print(nf.integer)
