From: dblack@...
Date: 2007-08-12T20:37:10+09:00
Subject: Re: Split a string based on change of character

Hi --

On Sun, 12 Aug 2007, botp wrote:

> On 8/11/07, dblack@rubypal.com <dblack@rubypal.com> wrote:
>>> s = "ZBBBCZZ"
>>> x = s.split('').group_by{|x| x}.entries
>>>
>>> or possibly to
>>>
>>> x = s.split('').group_by.entries
>>
>> I'm going to have to get special glasses that can read invisible
>> ink.... :-)
>
> whoops, sorry =)
> that should be
>
> fr
>   x = s.split('').group_by{|x| x}.entries.map{|x| x.join}
>
> to
>   x = s.split('').group_by.entries.map{|x| x.join}
>
> i assume that group_by without a block would group the elements by
> themselves. maybe i should name it group not group_by   :)

Actually I think group_by with nothing specified just returns an
enumerator over the array itself, so it probably will never be used (I
hope :-)

I don't think group_by will work for this problem, though, because it
groups everything together:

irb(main):014:0> s
=> "AABCDAAE"
irb(main):015:0> s.split(//).group_by {|x| x }.map {|e| e.join }
=> ["AAAAA", "CC", "EE", "DD", "BB"]

Notice how all the A's got put in one result.


David

-- 
* Books:
   RAILS ROUTING (new! http://www.awprofessional.com/title/0321509242)
   RUBY FOR RAILS (http://www.manning.com/black)
* Ruby/Rails training
     & consulting:  Ruby Power and Light, LLC (http://www.rubypal.com)