On Wed, Nov 18, 2009 at 2:22 PM, Themis Bourdenas < t.bourdena...@imperial.ac.uk> wrote:
> It's nothing in the library that completely imitates the slice without the > copies, right? You might be interested in my blist extension type (link below). Syntactically, using a blist is just like using a list, but it has different performance characteristics. In particular for your needs, taking a slice is cheap. The blist implements copy-on-write behind the scenes, so taking a slice takes O(log n) time, where n is the size of the initial blist. http://pypi.python.org/pypi/blist/ Here is a simple example, which creates a blist with over 500 million elements and takes a slice of over 500 million elements. In under 22 microseconds. :-) from blist import blist small_list = blist([0]) BIG_list = small_list * 2**29 BIG_slice = BIG_list[4:-5] Cashew:~$ python2.5 -m timeit -s 'from blist import blist' 'small_list=blist([0])' ''BIG_list=small_list*2**29' 'BIG_slice=BIG_list[4:-5]' 10000 loops, best of 3: 21.5 usec per loop -- Daniel Stutzbach, Ph.D. President, Stutzbach Enterprises, LLC <http://stutzbachenterprises.com>
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