Summing a 2D list
BJörn Lindqvist
bjourne at gmail.com
Fri Jun 13 08:54:11 EDT 2008
On Fri, Jun 13, 2008 at 2:12 PM, Karsten Heymann
<karsten.heymann at blue-cable.net> wrote:
> Although your problem has already been solved, I'd like to present a
> different approach which can be quite a bit faster. The most common
> approach seems to be using a dictionary:
>
> summed_up={}
> for user,vote in pairs:
> if summed_up.has_key(user):
> summed_up[user]+=vote
> else:
> summed_up[user]=vote
You'll save even more by using:
if user in summed_up:
instead of has_key.
--
mvh Björn
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