Question

如何逐一打印类的所有实例？

这是代码：

class Person:
    def __init__(self, fname, lname, age, gender):
       self.fname = fname
       self.lname = lname
       self.age = age
       self.gender = gender

class Children(Person):
    def __init__(self, fname, lname, age, gender, friends):
        super().__init__(fname, lname, age, gender)

        self.friends = friends

a100 = Children("a1", "a10", 17, "male", "a2 , a3 , a4 , a5")
a200 = Children("a2", "a20", 17, "male", "a5, a1, a4, a3 ")
a300 = Children("a3", "a30", 17 , "male", "a2, a1")
a400 = Children("a4", "a40", 17, "female", "a1, a2")
a500 = Children("a5", "a50", 16, "male", "a2, a1")

x = ["a100", "a300", "a500", "a200", "a400"]
for n in x:
    print(n.age)

错误是：

Traceback (most recent call last):
  File "ex1.py", line 23, in <module>
    print(n.age)
AttributeError: 'str' object has no attribute 'age'

Answer 1

如错误消息所提示，您正在尝试访问字符串对象的age属性。这是因为n是循环访问列表x的循环变量。

此列表包含一些令人困惑的字符串，因为它们代表了变量的“名称”。

您想要做的就是简单地更改列表以保留 actual 变量，而不是它们的名称作为字符串。像这样：

x = [a100, a300, a500, a200, a400]

Answer 2

您可以通过globals（）获得它们-返回当前所有全局对象的映射，如：

print([globals()[s].age for s in x])

如何一一打印一个类中的所有实例？

2 个答案: