Python Classes ( AttributeError: '' object has no attribute '')

Question

Having trouble understanding the problem in my code, new to classes (generally python too, so sorry if I name things wrong). I receive this error:

I think my code is too long winded to include in here, so I made a simplified version to test the concept below.

The question is, how can I create a new self object “self4”? Which would then be available to other functions within the class. Currently I get this error.

AttributeError: ‘className’ object has no attribute ‘self4’

class className(object):

   def __init__(self, self1=1,self2=2,self3=3):
        self.self1=self1
        self.self2=self2
        self.self3=self3

   def evaluate(self, self5):
        print className.func1(self) + className.func2(self)
        self.self5=self5
        print className.func1(self)

   def func1(self):
       return self.self1 + self.self5

   def func2(self):
       self.self4 = self.self1+self.self2+self.self3
       return self.self4

filename tester.py

import tester.py

mst=tester.className()

mst.evaluate()

Asked By: William Baker Morrison

||

Source

Answer 1

You should pass self4 in method.

Answered By: Manu

Answer 2

Edit:
Your code works fine!
What is the Problem?

I still think it is better to move self4 into the init!

Original
I think the most logical thing would be to define self4 on init:

class className(object):
    def __init__(self, self1=1, self2=2, self3=3):
        self.self1 = self1
        self.self2 = self2
        self.self3 = self3
        self.self4 = None

   #rest of class

Answered By: JDurstberger

Answer 3

If anyone still has this issue: you get this error when your indentation is goofed.To fix the asked question above, you just have to add a space before the last two functions definitions, that is;

class className(object):
    

    def __init__(self, self1=1,self2=2,self3=3):
        self.self1=self1
        self.self2=self2
        self.self3=self3

    def evaluate(self, self5):
        
        print className.func1(self) + className.func2(self)
        self.self5=self5
        print className.func1(self)

    def func1(self):
        return self.self1 + self.self5

    def func2(self):
        self.self4 = self.self1+self.self2+self.self3
        return self.self4

just make sure they all have similar indentation, and you are good to go.

Answered By: michael ditrick

Answer 4

If someone else ever gets this error and it is not an indentation problem, the error can also occur if you accidentally wrote ; Instead of : for the type annotation:

>>> class Example:
...     def __init__(self, var: str) -> None:
...         self.var; str = var
... 
>>> Example('foo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in __init__
AttributeError: 'Example' object has no attribute 'var'

Answered By: Yogev Neumann

Python Classes ( AttributeError: '' object has no attribute '')

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