[Zope-dev] Re: Unexpected Behaviour iterating over catalog search...

[Tres Seaver]

Chris Withers wrote:

> I have something like this:
> 
> for brain in Catalog(some_index=some_value):
>     # delete the object, and then
>     Catalog.uncatalog_object(brain.getPath())
> 
> ...which wasn't deleting all objects where some_index=some_value.
> 
> On a hunch, I tried:
> 
> for brain in tuple(Catalog(some_index=some_value)):
>     # delete the object, and then
>     Catalog.uncatalog_object(brain.getPath())
> 
> ...which magically worked.
> 
> Surely the thing returned by a Catalog search should be immutable?

Nope, it is "lazy";  immutability would require "realizing" it first, 
which would be prohibitively expensive in many cases.  Wrapping 'list()' 
around the result set would've worked, too.

Tres.
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Tres Seaver                                tseaver at zope.com
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