From: timr Date: 2009-06-21T16:10:37+09:00 Subject: regular expression gurus--help! I want all possible three letter sets for a string. Scan does this: irb> >>"abcdefghijkl".scan(...) # >> abc # >> def # >> ghi # >> jkl But I need: # >> abc # >> bcd # >> cde # >> def etc. I used to know the secret spell, but forgot it. Does anyone know how to do this with regular expression--basically need to force the index to advance one position rather than to the end of a match before starting the next attempt. Thanks in advance, Tim