标签：数据 util track type mod bsp tran data float
dataclasses 模块
本节主要讲述dataclasses的dataclass,field
导入： from dataclasses import dataclass, field
1.This module provides a decorator and functions for automatically adding generated special methods such as __init__() and __repr__() to user-defined classes.
举个例子：定义一个数据类，数据类中定义一个方法
from dataclasses import dataclass @dataclass class InventoryItem: """Class for keeping track of an item in inventory.""" name: str unit_price: float quantity_on_hand: int = 0 def total_cost(self) -> float: total_ct = self.unit_price * self.quantity_on_hand return total_ct if __name__ == ‘__main__‘: a = InventoryItem("zhangsan", 2.0, 3) print(a) # InventoryItem(name=‘zhangsan‘, unit_price=2.0, quantity_on_hand=3) print(a.total_cost()) # 6.0
①在total_cost()方法中,可以用self.unit_price......这种用法，就说明被dataclass装饰的类，根据类中定义的name，unit_price。。。会自动生成一个__init__方法，即：
会自动生成：（Note that this __init__ method is automatically added to the class）
def __init__(self, name: str, unit_price: float, quantity_on_hand: int = 0): self.name = name self.unit_price = unit_price self.quantity_on_hand = quantity_on_hand
②类中定义的变量没有赋值时，可以实例化对象进行赋值，如上述的a对象
类中定义的变量有赋值，可以实例化对象时，可以修改（参考默认参数），上面例子中 quantity_on_hand 定义format 为0，实例对象为3
③类中的所有参数都有默认值时，可以用fields方法获取每个变量的filed, 再进行field取值，
举例：
class InfoManage: """Info manage.""" name: str = ‘zhangsan‘ age: int = 23 hight: float = 180.0 field_types = {field.name: getattr(InfoManage, field.name) for field in fields(InfoManage)} print(field_types) # {‘name‘: ‘zhangsan‘, ‘age‘: 23, ‘hight‘: 180.0}
more to add......
标签：数据 util track type mod bsp tran data float
原文地址：https://www.cnblogs.com/ananmy/p/14791002.html
