From: "David A. Black" <dblack@...>
Date: 2004-07-07T22:25:39+09:00
Subject: Re: Regexp exercise

Hi --

On Wed, 7 Jul 2004, Olivier D. wrote:

> Hi,
> I have a string from which I want to extract a value. I have found four
> different methods to do it:
> 
> string = "a: 1, b: 2, c: 3"
> # let's say I want the value associated with b (2)
> 
> # 1st method:
> value = string[/b: \d+/][/\d+/]
> 
> # 2nd method:
> value = string.scan(/b: (\d+)/)[0][0]
> 
> # 3rd method:
> value = nil
> string.scan(/b: (\d+)/) { |val| value = val }
> 
> These three methods aren't clean and easy to understand.
> 
> I think that the best way to do it would be to use a simple match
> operator like:
> value = $1 if string =~ /b: (\d+)/

In addition to the other answers, if you want to grab the value as an
integer, you could do:

  require 'scanf'
  str = "a: 1, b: 2, c: 3"
  val, = str.scanf("%*[^b]b: %d")
  p val       # => 2


David

-- 
David A. Black
dblack@wobblini.net