Question

I have a code in which I want to defina a class function inside a class function. Here’s a simpler example of what I want to do. The goal of this program is to print 4.

>>> class bluh:
...     def haha(self):
...             print 3
...     def __init__(self):
...             def haha(self):
...                     print 4
... 
>>> x = bluh()
>>> x.haha()
3

How should I actually write this program to do what I want?

Answer 1

This really depends on what you want to do.

>>> class Foo(object):
...     def haha(self):
...         print 3
...     def __init__(self):
...         def haha():
...             print 4
...         self.haha = haha
... 
>>> a = Foo()
>>> a.haha
<function haha at 0x7f4539e25aa0>
>>> a.haha()
4

In the previous example, haha isn’t actually a method — It’s just a function. But it will pick up a reference to self from the closure and a lot of the time, that’s probably good enough. If you actually want to monkeypatch/duck punch a new method on an instance, you’ll need to use types.MethodType. See here for an example.