[Tutor] Importing sub modules

[Steven D'Aprano]

Prasad, Ramit wrote:
> The joins are really just random calls. I was just curious if importing os.path could avoid any reading/overhead that might occur by importing os.

No.

Python has no way of knowing what os.path is until it has imported os 
and can do an attribute lookup on os.path. This is determined at runtime 
by the os module, and depends on your operating system:

 >>> import os.path
 >>> os
<module 'os' from '/usr/lib/python2.4/os.pyc'>
 >>> os.path
<module 'posixpath' from '/usr/lib/python2.4/posixpath.pyc'>


DO NOT try importing posixpath (or equivalent for other OSes) directly, 
always use os.path.



-- 
Steven