question on list comprehensions

[Frohnhofer, James]

Not sure what you're trying to accomplish.  Either there's a typo or you need
to unsimplify the problem a bit (or both).

As far as I can tell

res=[49995000.0]

is equivalent to 

res=[0]
for i in arange(10000):
  res[0]=res[0]+i

> -----Original Message-----
> From: python-list-bounces+james.frohnhofer=csfb.com at python.org
> [mailto:python-list-bounces+james.frohnhofer=csfb.com at python.org]On
> Behalf Of Darren Dale
> Sent: Thursday, October 14, 2004 10:37 AM
> To: python-list at python.org
> Subject: question on list comprehensions
> 
> 
> Hi,
> 
> I need to replace the following loop with a list comprehension:
> 
> res=[0]
> for i in arange(10000):
>  res[0]=res[0]+i
> 
> In practice, res is a complex 2D numarray. For this reason, 
> the regular
> output of a list comprehension will not work: constructing a 
> list of every
> intermediate result will result in huge hits in speed and memory.
> 
> I saw this article at ASPN:
> http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204297
> 
> def thislist():
>     """Return a reference to the list object being constructed by the
>     list comprehension from which this function is called. Raises an
>     exception if called from anywhere else.
>     """
>     import sys
>     d = sys._getframe(1).f_locals
>     nestlevel = 1
>     while '_[%d]' % nestlevel in d:
>         nestlevel += 1
>     return d['_[%d]' % (nestlevel - 1)].__self__
> 
> Could the list comprehension include something like 
> thislist().pop(0), to be
> called when len(thislist)>1? (I think this could work, but am having
> trouble with the syntax.) Or is there a better way to 
> approach the problem?
> 
> Thank you,
> 
> Darren
> -- 
> http://mail.python.org/mailman/listinfo/python-list
> 

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