I need __closure__

I just checked out this very interesting mindmap:

http://www.mindmeister.com/10510492/python-underscore

And I was wondering what some of the new ones mean, like __code__ and __closure__. I googled around开发者_如何学Python but nothing concrete. Does anyone know?

From What's New in Python 3.0

The function attributes named func_X have been renamed to use the __X__ form, freeing up these names in the function attribute namespace for user-defined attributes. To wit, func_closure, func_code, func_defaults, func_dict, func_doc, func_globals, func_name were renamed to __closure__, __code__, __defaults__, __dict__, __doc__, __globals__, __name__, respectively.

Basically, same old Python 2 stuff, fancy new Python 3000 name.

You can learn more about most of these in PEP 232

You actually have analogous fields in CPython 2.x:

>>> first = lambda x: lambda y: x
>>> f = first(2)
>>> type(f.func_code)
<type 'code'>
>>> map(type, f.func_closure)
[<type 'cell'>]

Edit: For more details on the meaning of these constructs please read about "user defined functions" and "code objects" explained in the Data Model chapter of the Python Reference.

They used to be called

func_closure (now __closure__), func_code (now __code__)

(that should help googling).

A short explanation from here below.

• func_closure: None or a tuple of cells that contain bindings for the function’s free variables (read-only)
• func_code: The code object representing the compiled function body (writable)

These are Python's special methods.