From: "Peña, Botp" <botp@...>
Date: 2007-08-13T13:22:20+09:00
Subject: Re: Split a string based on change of character

From: James Edward Gray II [mailto:james@grayproductions.net] 
#  >> require "strscan" # => true
#  >> scanner = StringScanner.new("ZBBBCZZ") # => #<StringScanner 0/7 @ "ZBBBC...">
#  >> char_runs = Array.new # => []
#  >> char_runs << scanner.matched while scanner.scan(/(.)\1*/m) # => nil
#  >> char_runs # => ["Z", "BBB", "C", "ZZ"]

i just started playing w string scan after getting a hint fr dblack and reading this rubyish example fr James. i think stringscanner is an ideal solution for string scanning related problems.  I noticed that stringscanner#scan returns the match, so,

irb> s = StringScanner.new("ZBBBCZZ") 
=> <StringScanner 0/7 @ "ZBBBC...">
irb> a=[]  
=> []
irb> a << x while  x=s.scan(/(.)\1*/m)  
=> nil
irb> a     
=> ["Z", "BBB", "C", "ZZ"]

again, short and readable. ruby rocks.
kind regards -botp

ps: stringscanner docs are here http://www.ruby-doc.org/stdlib/libdoc/strscan/rdoc/index.html