Stack in Python: print a list

Question

I have stack code:

class Stack:
def __init__(self):
    self.__data = []

def empty(self):
    return len(self.__data) == 0

def size(self):
    return len(self.__data)

def push(self, x):
    self.__data.append(x)

def pop(self):
    return self.__data.pop()

and adds numbers 1, 2:

stack = Stack()
stack.push(1)
stack.push(2)

and I don't know how to print __data list? so that it shows 1,2 in the list?

[1,2]

Answer 1

You can use __str__ method to print the values using print() or __repr__ for direct representation.

class Stack:
    def __init__(self):
        self.data = []

    def empty(self):
        return len(self.data) == 0

    def size(self):
        return len(self.data)

    def push(self, x):
        self.data.append(x)

    def pop(self):
        return self.data.pop()
    
    def __str__(self):
        return str(self.data)

    def __repr__(self):
        return str(self.data)

>>> stack = Stack()
>>> stack.push(1)
>>> stack.push(2)
>>> print(stack)  ## using __str__
# [1, 2]
>>> stack         ## using __repr__
# [1, 2]