How to avoid explicit ‘self’ in Python?

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Python requires specifying self. The result is there’s never any confusion over what’s a member and what’s not, even without the full class definition visible. This leads to useful properties, such as: you can’t add members which accidentally shadow non-members and thereby break code.

One extreme example: you can write a class without any knowledge of what base classes it might have, and always know whether you are accessing a member or not:

class A(some_function()):
  def f(self):
    self.member = 42
    self.method()

That’s the complete code! (some_function returns the type used as a base.)

Another, where the methods of a class are dynamically composed:

class B(object):
  pass

print B()
# <__main__.B object at 0xb7e4082c>

def B_init(self):
  self.answer = 42
def B_str(self):
  return "<The answer is %s.>" % self.answer
# notice these functions require no knowledge of the actual class
# how hard are they to read and realize that "members" are used?

B.__init__ = B_init
B.__str__ = B_str

print B()
# <The answer is 42.>

Remember, both of these examples are extreme and you won’t see them every day, nor am I suggesting you should often write code like this, but they do clearly show aspects of self being explicitly required.

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