Slow comparison between two lists

[Steven D'Aprano]

On Thu, 23 Oct 2008 05:03:26 -0700, Jani Tiainen wrote:

> But in my case running that loop takes about 10 minutes. What I am doing
> wrong?

Others have already suggested you have a O(N**2) algorithm. Here's an 
excellent article that explains more about them:

http://www.joelonsoftware.com/articles/fog0000000319.html


The article is biased towards low-level languages like C. In Python the 
way to avoid them is to use sets or dicts, or to keep the list sorted and 
use the bisect module.


-- 
Steven