Static vs instance methods of str in Python

Question

So, I have learnt that strings have a center method.

>>> \'a\'.center(3)
\' a \'

Then I have noticed that I can do the same thing

Answer 1

To expand on RichieHindle's answer:

In Python, all methods on a class idiomatically take a "self" parameter. For example:

def method(self, arg): pass

That "self" argument tells Python what instance of the class the method is being called on. When you call a method on a class instance, this is typically passed implicitly for you:

o.method(1)

However, you also have the option of using the class Object, and explicitly passing in the class instance:

C.method(o, 1)

To to use your string example, str.center is a method on the str object:

"hi".center(5)

is equivalent to:

str.center("hi", 5)

You are passing in the str instance "hi" to the object, explicitly doing what's normally implicit.