variable update
Steve Holden
steve at holdenweb.com
Tue Sep 12 10:24:16 EDT 2006
Fredrik Lundh wrote:
> km wrote:
>
>
>>Is there any handy untility for checking if a variable is populated at
>>runtime ?
>
>
> access it, and catch the NameError:
>
> try:
> variable
> except NameError:
In a function when accessing a not-yet-bound local variable you may also
(as Fredrik knows but didn't bother to say) see an UnboundLocalError
exception,
> print "not defined"
> else:
> print "defined"
>
> leaving variables undefined is usually bad style, though; if you can,
> assign some value to it, and test for that value instead:
>
> variable = None
>
> ... lots of code that may assign to variable ...
>
> if variable is not None:
> print "not defined"
>
regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://holdenweb.blogspot.com
Recent Ramblings http://del.icio.us/steve.holden
More information about the Python-list
mailing list