[Tutor] __init__() - is it required?

[Steven D'Aprano]

Corey Richardson wrote:
> Do all classes need an __init__() method? I have classes that look much
> like this one starts out:
> 
> class GenerateXML(object):
>     """Defines methods to be inherited for StaticXML and AnimationXML"""
>     def __init__(self):
>         pass
> 
> I would rather not do that. Code without it runs fine, but will there be
> any negative consequences down the road? Does object define an __init__
> method for me?

You don't need to define an __init__ if you don't need one. A 
placeholder __init__ that does nothing, as above, is a waste of space.

object includes an __init__ method that not only does nothing, but 
ignores any arguments you pass to it:

 >>> object.__init__
<slot wrapper '__init__' of 'object' objects>
 >>> object.__init__(1, 2, 3)
 >>>

In Python 2.x, you can have "old-style" classes that don't inherit from 
object. They too don't need an __init__:

 >>> class Old:  # *don't* inherit from object
...     pass
...
 >>> o = Old()
 >>>


-- 
Steven