From: Robert Klemme <shortcutter@...>
Date: 2011-04-06T18:42:28+09:00
Subject: Re: Match a pattern multiple times, returning matches, captures and offset?

On Wed, Apr 6, 2011 at 3:37 AM, 7stud -- <bbxx789_05ss@yahoo.com> wrote:
> Markus Fischer wrote in post #991092:
>>
>> But here I'm missing the further possible matches, "_bar_" and "bar". Or
>> the #scan approach:
>>
>> ruby-1.9.2-p180 :004 > m = "_foo_ _bar_".scan(/_(\w+)_/)
>>  => [["foo"], ["bar"]]
>>
>> But in this case I've even less information, the match including _foo_
>> or _bar_ is not present and I can't get the offsets too.
>>
>> I re-read the documentation for Regexp#match
>
> If you look at the preamble in the docs for the MatchData class, you can
> retrieve a MatchData object using Regexp.last_match, which you can call
> inside a scan() block:

When doing nested matching it may be better to use $~ because that is
local to the current stack frame which Regexp.last_match isn't.
Example with relative offsets as well:

irb(main):022:0> str.scan /_(\w+)_/ do
irb(main):023:1* 2.times {|i| p [$~[i], $~.offset(i), $~.offset(i).map
{|o| o - $~.offset(0)[0]}]}
irb(main):024:1> end
["_foo_", [0, 5], [0, 5]]
["foo", [1, 4], [1, 4]]
["_bar_", [6, 11], [0, 5]]
["bar", [7, 10], [1, 4]]
=> "_foo_ _bar_"

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/