python int object is not callable?

Question

Relatively new to Python. I'm trying to practice linked list but I'm stuck with an error and couldn't figure out what the issue is.

The error:

    self.assertEqual(l.size(), 1)
    TypeError: 'int' object is not callable

The code:

from node import Node

class List:
    def __init__(self):
        self.head = None
        self.size = 0

    def add(self, item):
        temp = Node(item)
        temp.setNext(self.head)    # ERROR ON THIS LINE
        self.head = temp
        size += 1

    def size(self):
        return self.size

    ...

Node:

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

    ....

Test:

import unittest
import unorderedlist

class TestUnorderedList(unittest.TestCase):
    def test_add(self):
        l = unorderedlist.List()
        l.add(8)
        self.assertEqual(l.size(), 1)

if __name__ == '__main__':
    unittest.main()

It's funny because if I rename the size() to len and call it like l.len() it works fine. Anyone have a clue?

I'd suggest self._size for the data; that way you're not stomping on the method. — Charles Duffy
– Charles Duffy, Commented Oct 27, 2015 at 23:21
@PeterWood, ...well, that's the problem; in the code here, it's both at different times. — Charles Duffy
– Charles Duffy, Commented Oct 27, 2015 at 23:21

Daniel · Accepted Answer · 2015-10-27 23:20:06Z

3

With the line self.size = 0 you hide the methode size, so size is an int and not a method anymore.

answered Oct 27, 2015 at 23:20

Daniel

42.9k4 gold badges57 silver badges82 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Charles Duffy Over a year ago

I've typically seen the term "shadow" as opposed to "hide".

tuxtimo · Accepted Answer · 2015-10-27 23:22:54Z

0

You have hidden your method with the attribute. In your code you are then accessing the attribute which is of type int and so not callable. Avoid to name methods and attributes the same.

In case you want to achieve properties. There is the @property decorator:

@property
def size(self):
    return self._size

In your constructor you just define self._size and work internally with it.

answered Oct 27, 2015 at 23:22

tuxtimo

2,79023 silver badges29 bronze badges

Collectives™ on Stack Overflow

python int object is not callable?

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related