[Zope] Counting the elements of a result in a ZCatalog

[Marco Bizzarri]

On Thu, Jun 5, 2008 at 3:35 PM, Tino Wildenhain <tino at wildenhain.de> wrote:
> Hi,
>
> Marco Bizzarri wrote:
> ...
>>>
>>> if result:
>>>  result_len = results.actual_result_count
>>> else:
>>>  result_len = 0
>>>
>>> return result_len
>>>
> ...
>>
>> Thanks for your answer, but there is something I do not understand:
>>
>> if results:
>>
>> an empty result from ZCatlog is false in a boolen condition?
>
> Yes, thats standard Python behavior, empty lists, dictionaries
> and similar objects are assumed "False" when used as boolean.
>
> This means you could even write it this way:
>
> return (results and results.actual_result_count) or 0
>
> in python2.5 (not yet supported by Zope) even:
>
> return results.actual_result_count if results else 0
>
> Cheers
> Tino
>
>


Tino, Janko, thanks for the clarification. I understand the standard
behaviour of list and tuples. But what a Catalog returns is not (if I
understand it correctly) a list or a tuple, even though it presents as
such. It is a subclass of Lazy. Is Lazy behaving like a list or a
tuple, in this respect?

Regards
Marco




-- 
Marco Bizzarri
http://iliveinpisa.blogspot.com/