From: steve <zyzygy@...>
Date: 2009-10-15T17:15:21+09:00
Subject: Re: matching against a zillion patterns

George George wrote:
> i have some script in which i would like to match a string against
> 'many' regular expressions patterns.
> 
> def group(string)
>  if string=~ /pattern1 |patter2|pattern3|pattern(N)/  #where N =>100
>    group =1
> else
>  ....
>  end
> end
> 
> My worry is the amount of patterns that i have (exceeding 400) and the
> efficiency and sanity of such an approach.What would you advice?
> 
> 
> Thank you.

Are the matches randomly distributed across the patterns?  If not, 
perhaps you could arrange for the most common patterns in the first 
search, the next most common in a subsequent search and so on.

Also recall that compiled regexps can be assigned to variables or 
constants, including arrays.

Regards

Steve.