Python中访问类对象属性遇异常？列表存对象后属性访问问题求助

我尝试将Animal对象存入Animals类的animalList列表，但调用show方法时无法正确获取age和name属性，输出的是方法的内存地址。

原代码 #

class Animal:
    def __init__(self, age, name) -> None:
        self.age = age
        self.name = name
    
    def getAge(self):
        return self.age
    
    def getName(self):
        return self.name
    
class Animals:
    def __init__(self, index) -> None:
            self.index = index
            self.animalList = None
    
    def startInsert(self):
        newTable = list()
        for i in range(self.index):
            newTable.append(None)
        self.animalList = newTable
        
    def insertInIndex(self, index, animalObject):
        for i in range(len(self.animalList)):
            if i == index:
                self.animalList[i] = animalObject
    
    def show(this):
        for i in range(len(this.animalList)):
            if this.animalList[i] is not None:
                print('index: ',i,', Age: ',this.animalList[i].getAge,', Name: ',this.animalList[i].getAge)

animals = Animals(5)
animals.startInsert()
cow = Animal(2, "Cow")
dog = Animal(3, "Dog")
animals.insertInIndex(2, cow)
animals.insertInIndex(3, dog)
animals.show()

期望输出 #

index: 2, Age: 2, Type: Cow
index: 3, Age: 3, Type: Dog

实际输出 #

index:  2 , Age:  <bound method Animal.getAge of <__main__.Animal object at 0x00000200ead03cd0>> , Type:  <bound method Animal.getAge of <__main__.Animal object at 0x00000200ead03cd0>>
index:  3 , Age:  <bound method Animal.getAge of <__main__.Animal object at 0x00000200ead03c70>> , Type:  <bound method Animal.getAge of <__main__.Animal object at 0x00000200ead03c70>>

错误原因与修复方法 #

• 方法未调用：getAge和getName是实例方法，必须加括号()才能执行并返回属性值，直接写方法名会返回方法对象的内存地址。
• 字段调用错误：原show方法中两次调用了getAge，第二个应该改为getName()，同时输出文本要和期望一致，把Name改成Type。
• 可选优化：insertInIndex方法无需循环遍历，直接通过索引赋值即可；startInsert可以用列表生成式简化代码。

修正后的完整代码 #

class Animal:
    def __init__(self, age, name) -> None:
        self.age = age
        self.name = name
    
    def getAge(self):
        return self.age
    
    def getName(self):
        return self.name
    
class Animals:
    def __init__(self, index) -> None:
            self.index = index
            self.animalList = None
    
    def startInsert(self):
        # 用列表生成式简化初始化
        self.animalList = [None] * self.index
        
    def insertInIndex(self, index, animalObject):
        # 直接通过索引赋值，无需循环
        if 0 <= index < len(self.animalList):
            self.animalList[index] = animalObject
    
    def show(this):
        for i in range(len(this.animalList)):
            animal = this.animalList[i]
            if animal is not None:
                # 调用方法并修正输出文本
                print(f'index: {i}, Age: {animal.getAge()}, Type: {animal.getName()}')

animals = Animals(5)
animals.startInsert()
cow = Animal(2, "Cow")
dog = Animal(3, "Dog")
animals.insertInIndex(2, cow)
animals.insertInIndex(3, dog)
animals.show()

运行修正后的代码，输出结果与期望一致：

index: 2, Age: 2, Type: Cow
index: 3, Age: 3, Type: Dog

内容的提问来源于stack exchange，提问作者asker