From: Stefano Crocco <stefano.crocco@...>
Date: 2008-06-02T15:20:11+09:00
Subject: Re: Remove Parts of a String

On Monday 02 June 2008, Victor Reyes wrote:
>
> already spoke, after all, I am just learning Ruby. However, I do find that
> to understand:
>
>  str.gsub(/:[^,]*(?:$|(?=,))/,'').split( ',')
>
> you need a PhD in "General Expresionology". Ruby is supposed to be simple.
> Here you have 1 line of code but need 1 page to explain it. I do find it
> elegant, although I don't understand it. I only wish I could do that to!
>
> Victor

To understand it, you need to know regexps. The first argument of gsub is a 
regexp which matches all substrings starting with a colon, followed by any 
number of character except comma followed by a comma (which is not included in 
the match, which explains the use of the (?=,) construct). The second argument 
of gsub tells that the parts of the string matching the previous regexp should 
be replaced with an empty string. The returned string is then split at commas.

If you want a quick reference on regexps in ruby, you can look here: 
http://www.zenspider.com/Languages/Ruby/QuickRef.html#11. If you need a more 
complete introduction, there's a long description in the free edition of the 
Pickaxe: http://www.ruby-doc.org/docs/ProgrammingRuby/html/intro.html#S5

I hope this helps

Stefano