a problem with subclassing a dict

[David Eppstein]

In article <a8o0ro$1qoa at r02n01.cac.psu.edu>,
 Rajarshi Guha <rxg218 at psu.edu> wrote:

>   I was playing with some code from a tutorial by GvR 
...
> Traceback (most recent call last):
>   File "p2.py", line 22, in ?
>     print md[2]
> KeyError: 2

Your modified __getitem__ function appears not to be called even for the 
successful accesses (e.g. if you put a print statement before the try, 
it never gets printed).  The tutorial mentions a problem like this for 
local and global scope dictionaries, but doesn't say that it happens for 
other kinds of dictionaries too...

Someone more expert than I can tell you why this doesn't work, but
if you really need to define your own dictionary-lookalike class, you 
might also want to look at
<http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/117236>

-- 
David Eppstein       UC Irvine Dept. of Information & Computer Science
eppstein at ics.uci.edu http://www.ics.uci.edu/~eppstein/