------ art_6461_30171838.1137467977108 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Thanks for your replay. To make the problem clear. I want to only change the regular expression, but not the code to implement this function. Actually, the regular expression comes from a configurable table. I'll be supposed to only have the privilege to update the table. So What I really want is a alternative way to in place of the regular expression (?<!STR )SNPB 2006/1/17, James Edward Gray II <james / grayproductions.net>: > > On Jan 16, 2006, at 8:35 PM, Eric Luo wrote: > > > I need to hack out an regular expression, which will match "SNPB" > > without > > matching "STR SNPB". > > Since ruby 1.8.2 or 1.8.4 don't support the lookbehind feature. > > what's the > > workable regular expression > > for ruby version 1.8.2? > > Lookbehind is just lookahead, backwards. ;) > > >> tests = %w{SNPB STR\ SNPB} > => ["SNPB", "STR SNPB"] > >> tests.map { |t| t.reverse }.grep(/\bBPNS\b(?! RTS)/).map { |t| > t.reverse } > => ["SNPB"] > > Hope that helps. > > James Edward Gray II > > ------ art_6461_30171838.1137467977108--