How to know when a variable is set

[Michael Hudson]

madsurfer2000 at hotmail.com (-) writes:

> Michael Hudson <mwh at python.net> wrote in message news:<uvggdl5ek.fsf at python.net>...
> > madsurfer2000 at hotmail.com (-) writes:
> > 
> > > How can I test if a variable has been given a value, or if it's
> > > undefined?
> > 
> > Why would you want to do that?  Specificaly, in what context do you
> > want to know?
> > 
> 
> I like the idea of structs, and I was planning to use a class the same
> way, like
> 
> class info:
>     pass
> ...
> info.name = ... 

Oh.  In this case you'd want hasattr().  Or maybe try:/ except
AttributeError:.

> These would be set in an event driven GUI, and I needed to know if
> an attribute had been set before I saved the information. Now that I
> have thought more about it, an hash table would be a better choice.

Well, the above is only syntax sugar for a hash-table, as it happens.
But you're probably right.

Cheers,
M.

-- 
  In many ways, it's a dull language, borrowing solid old concepts
  from many other languages & styles:  boring syntax, unsurprising
  semantics, few  automatic coercions, etc etc.  But that's one of
  the things I like about it.                 -- Tim Peters, 16 Sep 93