From: "David A. Black" <dblack@...>
Date: 2009-08-29T08:01:17+09:00
Subject: Re: I need a string#all_indices method--is there such a thing?

Hi --

On Sat, 29 Aug 2009, Joel VanderWerf wrote:

> Bertram Scharpf wrote:
>> Hi,
>> 
>> Am Freitag, 28. Aug 2009, 17:40:05 +0900 schrieb timr:
>>> Scan gives you the matches, not the indices (which is what I need).
>>> 
>>>>> "this is a test for scan".scan(/t/)
>>> => ["t", "t", "t"]
>> 
>> There's a trick to do it with String#scan:
>>
>>   a = []
>>   "this is a test for scan".scan( /t/) { a.push $`.length }
>>   a
>> 
>> This does not work when the matches overlap.
>>
>>   "banana".scan /ana/       #=> ["ana"]
>> 
>> Bertram
>> 
>> 
>
> Same difficulty with overlap, but for variety:
>
> class String
>  def all_indexes re
>    a=[];scan(re) {a<<$~.begin(0)};a
>  end
> end

Just to add to the collection: there's also $~.offset(1)[0]


David

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