From: Bas van Gils <bas@...>
Date: 2007-06-12T16:55:36+09:00
Subject: Re: extracting numbers from a string

On Tue, Jun 12, 2007 at 03:45:04PM +0900, Matt Jones wrote:
> I have filenames from various digital cameras:  DSC_1234.jpg,
> CRW1234.jpg, etc.  What I really want is the numeric portion of that
> filename.  How would I extract just that portion?

Some solutions have been posted already, but here's mine:

  irb(main):001:0> s="DSC_1234.jpg"
  => "DSC_1234.jpg"
  irb(main):002:0> s.sub(/\D+(\d+).*/,'\1')
  => "1234"

basicially the regexp looks for :

  - one or more non-digits
  - one or more digits => because this is between parenthesis you can refer to
    it with \1 later on
  - something more

The digits (safely stored in \1) is all you want to keep... this assumed you
are only interested in the first sequence of numbers.

Cheers

  Bas

-- 
Bas van Gils <bas@van-gils.org>, http://www.van-gils.org
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