Why cant I access class variable from one of it's method as below in Python?

Question

I made a class named 'employee' as below. I can access the class variable 'company' directly through class itself but cant access it using 'getCompany()' method. What is wrong with my code? Since I am newbie to OOP concepts, please grant me detailed but step-wise elaboration of the concepts.

<!-- language: lang-python -->

>>> class employee:
    company = 'ABC Corporation'
    def getCompany():
        return company

>>> employee.company       #####this does as expected
'ABC Corporation'
>>> employee.getCompany()  #####what is wrong with this thing???
Traceback (most recent call last):
   File "<pyshell#15>", line 1, in <module>
     employee.getCompany()
   File "<pyshell#13>", line 4, in getCompany
     return company
NameError: name 'company' is not defined   #####says it is not defined

I am newbie to OOP concepts.

score 2 · Accepted Answer · answered Oct 22 '16 at 04:04

The interpreter is looking for a local variable of that name, which doesn't exist. You should also add self to the parameters, so that you have a proper instance method. If you want a static method instead of an instance method, you'll need to add the @staticmethod decorator. Finally, use the class name to refer to the class variable.

>>> class employee:
...     company = 'ABC Corporation'
...     def getCompany(self=None):
...             return employee.company
...
>>> employee.company
'ABC Corporation'
>>> employee.getCompany()
'ABC Corporation'
>>> e = employee()
>>> e.getCompany()
'ABC Corporation'
>>> e.company
'ABC Corporation'

Yeah, I got it. The main point was that the 'company' variable was not defined within the method. And we cant simply access the class variable only by class variable name. — Prakash Bhattarai, Oct 22 '16 at 12:18

score 0 · Answer 2 · edited May 23 '17 at 12:16

In [1]: class employee:
   ...:     company = "ABC Corporation"
   ...:     def getCompany(self):
   ...:         return self.company
   ...:

In [2]: employee.company
Out[2]: 'ABC Corporation'

In [3]: employee().getCompany()
Out[3]: 'ABC Corporation'

In [4]: class employee:
   ...:     company = "ABC Corporation"
   ...:
   ...:     @classmethod
   ...:     def getCompany(self):
   ...:         return self.company
   ...:

In [5]: employee.company
Out[5]: 'ABC Corporation'

In [6]: employee.getCompany()
Out[6]: 'ABC Corporation'

Question Static class variables in Python has more details

Why cant I access class variable from one of it's method as below in Python?

I am newbie to OOP concepts.

2 Answers2