Using a class method in __init__

Question

I have the following class, where I want to use the method location_change within __init__for that class. Is there a way to do this? The example I use below is a simplification but what I need to do is use a class method to transform some constructor data. Can this be done in python?

class dummy:
 def __init__(self):
 self.location = 'USA'
 print(self.location)
 location_change()
 print(self.location)
 def location_change():
 self.location = 'UK'
first_dummy = dummy()

• demalexx: It's better to name classes in CamelCase.
• Katriel: There seems to be some confusion between classmethods and methods on classes; sadly, these are different.

Answer 1

Sure it can!

self.location_change()

each method in a class should take at least one argument and that is conventionally called self.

def location_change(self):

an introductory tutorial on oop in python http://www.voidspace.org.uk/python/articles/OOP.shtml

the documentation http://docs.python.org/tutorial/classes.html

Answer 2

Try this

class Dummy:
 def __init__(self):
 self.location = 'USA'
 print(self.location)
 self.location_change()
 print(self.location)
 def location_change(self):
 self.location = 'UK'
first_dummy = Dummy()

Answer 3

class Dummy:
 def __init__(self):
 self.location = 'USA'
 print(self.location)
 Dummy.location_change(self)
 print(self.location)
 def location_change(self):
 self.location = 'UK'
first_dummy = Dummy()
print(first_dummy)

What you needed to do was tell "location_change" that it was working with argument, self. Otherwise it's an undefined variable. You also needed to use the class name when calling it. This should give you:

USA
UK
<__main__.Dummy object at 0x1005ae1d0>

• Rik Poggi: Why would you call dummy.location_change(self) instead of self.location_change()? This way if a sub-class implement location_change that implementation will not be used!