I defined a two classes within one file. I was able to have it run after separating the classes into two files, but I wanted to know why the first attempt does not work.
The traceback read:
Traceback (most recent call last):
File "Polygon.py", line 15, in <module>
class Triangle(Polygon):
File "Polygon.py", line 21, in Triangle
print(self.sides)
NameError: name 'self' is not defined
and the bare bones of my code was as follows
class Polygon:
def __init__(self, no_of_sides):
self.n = no_of_sides
self.sides = [0 for i in range(no_of_sides)]
class Triangle(Polygon):
def __init__(self):
Polygon.__init__(self,3)
It threw the same NameError when I ran this as the body of class Triangle
class Triangle(Polygon):
self.a = 1
It looks like what you are trying to do, is define a class attribute a in class Triangle. You don't need self to do that. self is used to access the object instance of a class.
If you would want to define a as an object attribute rather than a class attribute, you should do something like:
class Triangle(Polygon):
def __init__(self):
Polygon.__init__(self, 3)
self.a = 1
In this case, a is only defined upon class instantiation and accessible as Triangle().a, or as self.a inside other object-scope methods.
And if you want to define a as a class attribute, simply do:
class Triangle(Polygon):
a = 1
def __init__(self):
...
In this case, a is defined upon class definition and accessible even before instantiation, as Triangle.a