python面向对象设计案例

类设计案例

# 设计一个闹钟类
class Clock:
	id = None
	price = None
	
	def ring(self):
		print("叮铃铃")
 
# 构建两个闹钟并让其工作
clock1 = Clock()
clock1.id = "003032"
clock1.price = 19.99
print(f"闹钟id:{clock1.id}, 价格:{clock1.price}")
clock1.ring() # 工作
 
clock2 = Clock()
clock2.id = "003033"
clock2.price = 21.99
print(f"闹钟id:{clock2.id}, 价格:{clock2.price}")
clock2.ring()

封装设计案例

class Phone:
	__is_5g_enable = False
	
	#
	def __check_5g(self):
		if self.__is_5g_enable:
			print("5g开启")
		else:
			print("5g关闭")
	
	#
	def call_by_5g(self):
		self.__check_5g()
		print("通话中")
 
phone = Phone()
phone.call_by_5g() # output:5g关闭 通话中

继承设计案例

单继承

class Phone:
	IMEI = None # 序列号
	producer = 'HM' # 厂商
	
	#
	def call_by_5g(self):
		print("5g通话")
 
class Phone2022(Phone): # python继承语法
	face_id = "10001"
	
	#
	def call_by_6g(self):
		print("6g通话")
 
phone = Phone2022()
print(phone.producer) # output:HM    继承的东西可直接使用
phone.call_by_5g() # output:5g通话    
phone.call_by_6g() # output:6g通话

多继承

class Phone:
	IMEI = None # 序列号
	producer = 'XM' # 厂商
	
	#
	def call_by_5g(self):
		print("5g通话")
 
class Phone2022(Phone): # python继承语法
	face_id = "10001"
	
	#
	def call_by_6g(self):
		print("6g通话")
 
class NFCReader:
	nfc_type = "第五代"
	producer = "HM"
	
	#
	def read_card(self):
		print("NFC读")
	
	#
	def write_card(self):
		print("NFC写")
 
class RemoteControl:
	rc_type = "红外遥控"
	
	def control(self):
		print("红外遥控开启")
 
class MyPhone(Phone, NFCReader, RemoteControl):
	pass # output:继承后跳过
 
phone = MyPhone()
phone.call_by_5g() # output:5g通话
phone.read_card() # output:NFC读
phone.write_card() # output:NFC写
phone.control() # output:红外遥控开启
print(phone.producer) # output:XM    多继承左优先

多态设计案例

# 类似cpp中的virtual
class Animal:
	def speak(self):
		pass
 
class Dog(Animal):
	def speak(self):
		print("wangwang")
 
class Cat(Animal):
	def speak(self):
		print("miaomiao")
 
def sound(animal: Animal):
	animal.speak()
 
dog = Dog()
cat = Cat()
sound(dog)
sound(cat)
# output:
# wangwang
# miaomiao

抽象类

class AC:
	def cool_wind(self):
		pass
	
	#
	def hot_wind(self):
		pass
	
	#
	def swing_l_r(self):
		pass
 
class Midea_AC(AC):
	def cool_wind(self):
		print("美的冷风")
	
	#
	def hot_wind(self):
		print("美的热风")
	
	#
	def swing_l_r(self):
		print("美的摇头")
 
class Gree_AC(AC):
	def cool_wind(self):
		print("格力冷风")
	
	#
	def hot_wind(self):
		print("格力热风")
	
	#
	def swing_l_r(self):
		print("格力摇头")

最佳实践案例

这个案例可以直接复制到 .py 文件中运行。它把“属性、方法、封装、异常、计算属性”放到一个更贴近真实代码的类里。

from dataclasses import dataclass, field
 
 
@dataclass
class Course:
    name: str
    scores: list[int] = field(default_factory=list)
 
    def add_score(self, score: int) -> None:
        if not 0 <= score <= 100:
            raise ValueError("score must be between 0 and 100")
        self.scores.append(score)
 
    @property
    def average(self) -> float:
        return sum(self.scores) / len(self.scores) if self.scores else 0.0
 
    @property
    def passed_count(self) -> int:
        return sum(1 for score in self.scores if score >= 60)
 
 
def main():
    python = Course("Python")
    python.add_score(80)
    python.add_score(95)
    python.add_score(50)
 
    print(python.name)
    print(f"average={python.average:.1f}")
    print(f"passed_count={python.passed_count}")
 
 
if __name__ == "__main__":
    main()