http://snippets.dzone.com/posts Thu, 24 Jul 2008 12:43:49 GMT DZone Snippets: anchors code http://snippets.dzone.com/posts/show/5062 Anchors are about finding matches beginning with or ending with a certain pattern. <br /> <br />This example from an irb session helps to show what \b, \w, ^, $ and \B do. \b - matches a word boundary, \w - matches a word character, ^ - matches a character at the beginning of a line, $ - matches the character at the end of a line, and \B matches a word boundary charcter which does not match \w. <br /> <br /><code> <br />irb(main):010:0> "paella"[/\ba/] <br />=> nil <br />irb(main):013:0> "artistic paella wake"[/\wa/] <br />=> "pa" <br />irb(main):026:0> "artistic paella wake"[/\B.[a-z]a$/] <br />=> nil <br />irb(main):027:0> "artistic paella wake"[/\B.[a-z]$/] <br />=> "ke" <br />irb(main):039:0> "artistic paella wake"[/\B./] <br />=> "r" <br />irb(main):040:0> "artistic paella wake"[/\Ba./] <br />=> "ae" <br />irb(main):044:0> "artistic paella wake"[/[^\B.{3}]/] <br />=> "a" <br />irb(main):046:0> "artistic paella wake"[/[^\B.]{3}/] <br />=> "art" <br />irb(main):047:0> "artistic paella wake"[/[^\w]{3}/] <br />=> nil <br />irb(main):047:0> "artistic paella wake"[/[^\w]{3}/] <br />=> nil <br />irb(main):048:0> "artistic paella wake"[/[^\br]{3}/] <br />=> "tis" <br />irb(main):050:0> "artistic paella wake"[/[^\b]{3}/] <br />=> "art" <br />irb(main):051:0> "artistic paella wake"[/[^\ba]{3}/] <br />=> "rti" <br />irb(main):054:0> "artistic paella wake"[/\ba/] <br />=> "a" <br />irb(main):055:0> "artistic paella wake"[/\ba./] <br />=> "ar" <br />irb(main):058:0> "people paella wake"[/\bp./] <br />=> "pe" <br />irb(main):060:0> "apostrophe paella wake"[/\bpa./] <br />=> "pae" <br />irb(main):061:0> "apostrophe paella wake"[/\bp./] <br />=> "pa" <br />irb(main):062:0> "apostrophe paella wake"[/\Bp./] <br />=> "po" <br />irb(main):064:0> "pancake paella wake"[/\Bp./] <br />=> nil <br />irb(main):065:0> "anticipated paella wake"[/\Bp./] <br />=> "pa" <br />irb(main):066:0> "anticipated paella wake"[/\Bp../] <br />=> "pat" <br />irb(main):067:0> "anticipated paella wake"[/\wp../] <br />=> "ipat" <br /> <br /></code> Thu, 31 Jan 2008 11:04:20 GMT http://snippets.dzone.com/posts/show/5062 jrobertson (James Robertson)