Python。它不是打印 Stack 对象的实际值，而是 returns 该对象的地址

Question

不是打印 Stack 对象的实际值，而是 returns 该对象的地址。

class 堆栈： def init(self): self._theItems = 列表()

def push(self, item):
    self._theItems.append(item)

def pop(self):
    assert not self.is_empty(), "Cannot pop from an empty stack"
    return self._theItems.pop()

def get_top(self):
    assert not self.is_empty(), "Cannot peek at an empty stack"
    return self._theItems[-1]

def is_empty(self):
    return len(self._theItems) == 0

def display(self):
    return self

Answer 1

那是因为您还没有定义任何repr 或str 方法。请按如下所示修改程序：

    def __str__(self):
        return f'The customized stack has values: {self._theItems}'

    def __repr__(self):
        return self.__str__()

    def display(self):
        return self.__repr__()

if __name__ == "__main__":
    customized_stack = Stack()
    customized_stack.init()
    customized_stack.push(10)
    customized_stack.push(20)
    customized_stack.push(30)
    customized_stack.push(40)
    print(customized_stack)

当你运行它时，你会得到：

The customized stack has values: [10, 20, 30, 40]

Python。它不是打印 Stack 对象的实际值，而是 returns 该对象的地址

Python. Instead of printing actual values from the Stack object it returns an address of that object

stack

python-3.x