2009/3/11 Emad Nawfal (عماد نوفل) <emadnaw...@gmail.com>:
> Now I know that I did not ask the right question. What I meant was: how to
> extract a sublist from a list whose length is unknown. Let's say I have a
> hundred of these lists and each of these has an NP somewhere, it could be
> nested in nested list, which is turn nested in another one and so on. The
> bottom line is that I do not know the index. To make things more concrete,
> this is a representative list. How can I extract all the sublists beginning
> with "NP" from it?
You'll have to do recursion - that is:
NPstart(alist) =
if alist starts with "NP":
alist + NPstart for all sublists of alist
else:
NPstart for all sublists of alist
Turning that into Python we get:
def NPstart(alist):
if isinstance(alist, basestring): # It's ugly to do an isinstance
in Python, but any better method would be fully changing your data
structure, so I use it for now
return []
else:
if alist[0] == 'NP':
return [alist] + [NPstart(sublist) for sublist in alist]
else:
return [NPstart(sublist) for sublist in alist]
--
André Engels, andreeng...@gmail.com
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