instance of class in python (fundamental explanation)

Question

When I create some class in python:

class Someclass():
   def __init__(self, some_arg):
       self.arg = some_arg

Then I create an instance of this class:

>>> some_instance = Someclass('something')

Then the output about our instance:

>>> some_instance
>>> <__main__.Someclass instance at 0x00000000021CA848>

Now I have few questions:

1) What does __main__ mean exactly in this example?

2) What does **at 0x00000000021CA848** mean, and what do I need this information for?

You need this information for debugging. When two variables, when printed, show the same address (hex number), you can assume they reference the same instance. — Fred Foo
– Fred Foo, Commented Nov 16, 2013 at 13:44

thefourtheye · Accepted Answer · 2013-11-16 13:43:35Z

5

__main__ is the module's name and 0x00000000021CA848 is the address of the object in memory, if you are using CPython.

Its the string representation of your object. You can use it for debugging.

answered Nov 16, 2013 at 13:43

thefourtheye

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