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]

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

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.

 

[Alex Martelli]

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

"if thecertainelement 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]

Hello,

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

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

Kent

 

[Marco Aschwanden]

what is the fastest way to determine whether list l (with
Either a sorted list (in conjunction with the bisect-module) or a
dictionary is your friend...

Regards,
Marco