nested exceptions?

[Aahz]

In article <a9t177$pi5$1 at panix1.panix.com>, Aahz <aahz at pythoncraft.com> wrote:
>In article <roy-AAA3A1.19193820042002 at news1.panix.com>,
>Roy Smith  <roy at panix.com> wrote:
>>
>>I want to look an oid up in my dictionary, and if it's not there, I want to 
>>keep working my way up the tree until I find it.  Thus, if 
>>'1.3.6.1.4.3.5.66.3.4' isn't a key, I want to try '1.3.6.1.4.3.5.66.3', and 
>>then '1.3.6.1.4.3.5.66', and then '1.3.6.1.4.3.5', and so on until I find 
>>it (if nothing else, '1' is guaranteed to be a key).
>>
>>What I've come up with uses recursion:
>>
>>    def getBaseObject (self, objects, oid):
>>        try:
>>           return objects[oid]
>>       except KeyError:
>>           return self.getBaseObject (objects, self.getParentOid (oid)) 
>
>I'd write this as
>
>    while not objects.has_key(oid):
>        oid = self.getParentOid(oid)
>    return objects[oid]

...and if you're using Python 2.2, write it as

    while oid not in objects:


Hmmmm....  it occurs to me that those of us teaching Python will need to
be *very* careful in making sure that people avoid 'in' over lists.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

What if there were no rhetorical questions?