fast list lookup

[Klaus Neuner]

Hello,

what is the fastest way to determine whether list l (with
len(l)>30000) contains a certain element?


Klaus

[Simon Brunning]

Re: fast list lookup

On Wed, 26 Jan 2005 06:45:29 -0800 (PST), Klaus Neuner
<klaus_neuner82 @yahoo.de> wrote:[color=blue]
> what is the fastest way to determine whether list l (with
> len(l)>30000) contains a certain element?[/color]

If the list isn't sorted, I doubt you'll do better than

if an_element in my_list:
# do whatever

If the list is sorted, have a look at the bisect module.

--
Cheers,
Simon B,
simon@brunningo nline.net,

http://www.brunningonline.net/simon/blog/

[Alex Martelli]

Re: fast list lookup

Klaus Neuner <klaus_neuner82 @yahoo.de> wrote:
[color=blue]
> what is the fastest way to determine whether list l (with
> len(l)>30000) contains a certain element?[/color]

"if thecertaineleme nt in l:"

is the fastest way unless there are properties of l which you're not
telling us about, or unless what you need is not just to determine
whether l contains a certain element but rather something different
(such as doing the same determination for several elements on an
unchanging l).


Alex

[Kent Johnson]

Re: fast list lookup

Klaus Neuner wrote:[color=blue]
> Hello,
>
> what is the fastest way to determine whether list l (with
> len(l)>30000) contains a certain element?[/color]

If you can use a set or dict instead of a list this test will be much faster.

Kent

[Marco Aschwanden]

Re: fast list lookup

>> what is the fastest way to determine whether list l (with[color=blue][color=green]
>> len(l)>30000) contains a certain element?[/color][/color]

Either a sorted list (in conjunction with the bisect-module) or a
dictionary is your friend...

Regards,
Marco