[Zope] checking for elements in a list

[J Cameron Cooper]

Christopher Rivard wrote:
> Hello,
> 
> I'm am trying to check for the membership of items in a list and think 
> I'm missing something.
> How is this done in dtml?
> 
> List allids: [15,16,17,18]
> 
> Check for multiple items in the list:
> 
> <dtml-in allids prefix="loop">
> <dtml-if expr="loop_item == 17">
> something
> <dtml-elif expr="loop_item == 17 and loop_item != 18">
> doesn't work
> </dtml-if>
> </dtml-in>
> 
> The goal is to check for combinations:
> 17 and not 18
> 18 only
> 17 only
> 17 and 15
> 18 and 16
> ...combinations.
> 
> I don't think that I really want to loop through the list, just want to 
> check membership in the list.

In Python, you can simply ask::

   17 in allids

   18 not in allids

and so forth as boolean expressions.

Just make sure that the elements of the list you're getting are what you 
think they are. If you ask about the integer 17 and the list actually 
has a string "17" they won't match. You can either adjust what you test 
or use something like the 'int' function to "cast".

		--jcc
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