From: "Peña, Botp" <botp@...>
Date: 2007-07-24T10:50:26+09:00
Subject: Re: finding positions in a string

From: bwv549 [mailto:jtprince@gmail.com] 
# substring_positions(my_substring, my_string)      # -> should return
# [0, 12, 29]
# 
# This seems trivial to do, but looking at StringScanner, String#match,
# and String#scan, nothing simple comes to mind.  There must be a one-
# liner somewhere for this kind of thing.  

not a raw one-liner, but you can create one ;)

root@pc4all:~# cat -n test.rb
     1  class String
     2     def scan_p ss
     3        a = []
     4        self.scan(ss){a << Regexp.last_match.begin(0)}
     5        a
     6     end
     7  end
     8
     9  p "this string this is a string this is it".scan_p("this")
    10
root@pc4all:~# ruby  test.rb
[0, 12, 29]
root@pc4all:~#

i think the keyword is Matchdata.

kind regards -botp