len() and __len__

[Greg Ewing]

Pete Shinners wrote:
> 
> len() will work on any type of sequence object (lists, tuples, and all).
> __len__ will only work on class instances with a __len__ method.

I think that, in Python 2.2, any object which responds
to len() also appears to have a __len__ method, due to
some magic which has been added to support subclassing
of builtin types.

--- 
Greg Ewing, Computer Science Dept, 
University of Canterbury,	  
Christchurch, New Zealand
http://www.cosc.canterbury.ac.nz/~greg