how many nested for can we utilize?
jr9445 at ATT.COM
Mon Aug 18 17:18:52 CEST 2008
> -----Original Message-----
> From: python-list-bounces+jr9445=att.com at python.org [mailto:python-
> list-bounces+jr9445=att.com at python.org] On Behalf Of Lie
> Sent: Monday, August 18, 2008 11:04 AM
> To: python-list at python.org
> Subject: Re: how many nested for can we utilize?
> On Aug 17, 4:23 pm, Fredrik Lundh <fred... at pythonware.com> wrote:
> > Patrol Sun wrote:
> > > when I use 20 for ,"SystemError: too many statically nested blocks"
> > > When I use 100 for ,"IndentationError: too many levels of
> > > How to handle these errors?
> > so why exactly are you trying to nest 20 or 100 for-in loops?
> > </F>
> I think most (all?) algorithm that might use 20+ levels of for-in
> loops could almost always be replaced with a recursive function. Or at
> least they could be broken into smaller functions.
Recursion is slow. There was a thread on permutations and I ran some timings on various methods of nesting loops. Also, I do remember hitting nested for limits very quickly. I think list comprehensions allowed for deeper nesting than straight for loops. Anyway, the thread contains various code and solutions that should help the OP.
Cookbook is relatively decent. 5 deep, 100 iterations:
list comprehension: 11.02
nested for loop : 13.16 +19%
cookbook : 18.85 +71%
recursion : 69.00 +526%
eval : 13.30 +20%
Start of thread: http://mail.python.org/pipermail/python-list/2008-January/473650.html
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