[Tutor] list slice

[Jerry Hill]

On Mon, Sep 15, 2008 at 10:56 AM, Norman Khine <norman at khine.net> wrote:
> Hello,
> I have this code:
>
> topics = object.parent.get_topics()
>        for i, topic in enumerate(topics):
>            all_previous_topics = topics[:i]
>            print all_previous_topics
>
> where topics returns a list.
>
> I am trying to get all the topics before current topic in the loop.
>
> Is there a way to do this?

Yes.

Is topics a list, or a function which returns a list?  What you've
written above works for me when topics is a list.  In what way doesn't
it work for you?

>>> topics = ['Reading', 'Writing', 'Arithmetic']
>>> for i, topic in enumerate(topics):
	print "Current Topic: ", topic
	print "Previous Topics: ", topics[:i]

	
Current Topic:  Reading
Previous Topics:  []
Current Topic:  Writing
Previous Topics:  ['Reading']
Current Topic:  Arithmetic
Previous Topics:  ['Reading', 'Writing']
>>>

-- 
Jerry