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List:       ruby-talk
Subject:    Re: Chopping the beginning of a string elegantly
From:       david () vallner ! net
Date:       2005-08-01 12:56:04
Message-ID: 1122900957.42ee1bddcca3a () mail ! atlantis ! sk
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Citát "francisrammeloo@hotmail.com" <francisrammeloo@hotmail.com>:

> I'm sorry but my first post was misleading.
> 
> The string actually looks like this:
> 
> "    BeginCaption         0, 20, 66, .."
> (the whitespace can be a combination of tabs and spaces)
> 
> So I actually have to cut out "Caption" word in the <<middle>> of the
> string.
> 
> Brian's hint got me on the right track. The solution I finally found
> was:
> 
> pane = line.sub(/\s*Begin(\w+).*/, '\1')
> 
> Unless some expert can prove a still more tight solution I believe I
> have found the best way to cut out the "Caption" part of the string.
> 
> Thank you all for your help.
> 
> Best regards,
> Francis
> 
> 
> 


Hmm. A wild guess (e.g. until there's a Windows installer for Ruby 1.9 w/
Oniguruma, or someone makes a SuSE compatible RPM for that) is that lookbehinds
in REs could reduce that to:

  pane = line[/(?<=Begin)\w+/]

There's a 95% chance you don't need those groups to catch the initial whitespace
and consume the rest of the string, so:

  pane = line.match(/Begin(\w+)/)[1]

also works and has a bit less noise. Weirdly though, Benchmark tells me it's
slightly slower. Guess you can't have your cake and eat it.

David
(ikkle newbie and all that)

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