CODEWITHSUNDEEP
pythonpython-3.x
PARADOXIAN PARADOX
PARADOXIAN PARADOX

Reputation: 13

attritbute error : ArrayStack object has no attribute len()

this is the code:

class Empty(Exception):
    pass

class ArrayStack:
    def __init__(self):
        self._data = []

    def __len(self):
        return len(self._data)

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

    def push(self, e):
        self._data.append(e)

    def pop(self):
        if self.is_empty():
            raise empty('Stack is Empty')
        return self._data.pop()

    def top(self):
        if self.is_empty():
            raise empty('Stack is Empty')
        return self._data[-1]

s= ArrayStack()
s.push(10)
s.push(20)
print('Stack: ', s._data)
**print('Length: ', len(s)) #this line is throwing the problem**
print('Is-Empty: ', s.is_empty())
print('Popped: ', s.pop())
print('Stack: ', s._data)

error message

Traceback (most recent call last): File "main.py", line 31, in print('Length: ', s.__len()) AttributeError: 'ArrayStack' object has no attribute '__len'

Upvotes: 1

Views: 886

Answers (2)

Rushikesh Sabde
Rushikesh Sabde

Reputation: 1626

In your ArrayStack Class your method __len() is typo mistake.

Your method should be len() because it is a magic method.

    def __len__(self):
    return len(self._data)

Upvotes: 2

Misslinska
Misslinska

Reputation: 92

You have a typo in your len definition. It should be __len__. I have noticed a second issue. You should capitalize 'empty' raise.

Upvotes: 0

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