From: "David A. Black" <dblack@...>
Date: 2009-08-31T23:42:43+09:00
Subject: Re: text lines manipulation

Hi --

On Mon, 31 Aug 2009, Bertram Scharpf wrote:

> Hi,
>
> Am Montag, 31. Aug 2009, 20:33:19 +0900 schrieb George George:
>>      m=Regexp.new(re,Regexp::IGNORECASE);
>>        if m.match(line)
>>           int1 = m.match(line)[1];
>>           c1   = m.match(line)[2];
>>           int2 = m.match(line)[3];
>>           puts int1<< c1 << int2
>>       end

To the OP: definitely lose the semi-colons :-)

> After `m.match(line)' the match is stored in the $~ global
> variable. You don't need to execute it three more times.
>
> $~[1]  is equivalent to  $1.
>
> The `<<' operator modifieds the string `int1'. Better is here the
> operator `+'.
>
> It's sure a matter of taste but in general shorter code is easier
> to read.
>
>  if line =~ /(\d+)(-)(\d+)/i then
>    int1 = $1
>    c1   = $2
>    int2 = $3
>    puts int1 + c1 + int2
>  end
>
> This is for the not faint-hearted:
>
>  int1, c1, int2 = *$~.captures

It's a little less formidable without the *, which should be OK. A
mixed solution:

   int1, c1, int2 = $1, $2, $3

or use Regexp#match and save the match explicitly.

   match = m.match(line)

   if match
     int1, c1, int2 = match.captures
   end

or similar.


David

-- 
David A. Black / Ruby Power and Light, LLC / http://www.rubypal.com
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