fastest table lookup

[Jeff Shannon]

Neal D. Becker wrote:

>I need a fairly small lookup table, and I'm wondering which data python data
>structure would be fastest.  I could use a list, tuple, dictionary, numeric
>array, or maybe plain python array.  The table would be indexed by simple
>integers and would be dense (filled).
>  
>

Which data structure will be fastest depends to some degree on the exact 
usage that it's being put to, but in most cases I expect that a 
dictionary will be the best bet.  IIRC, list (and tuple) indexing is 
O(n) (with n=len(list)), while dictionary references are O(1).  In some 
circumstances, it may (or may not) be possible to achieve further 
speedup by using a python array or numarray, but unless you're already 
planning on using numarray for other things, I'd consider its usage for 
a lookup table to be a premature optimization.

Jeff Shannon
Technician/Programmer
Credit International