note 77822 added to function.preg-replace

Once a match is identified, the regular expression engine appears to set aside the matching segment of the target string. A second segment that you expect to match may therefore end up not getting matched: // Expect 'pa pa pa pa' but get 'pa ma pa ma' echo preg_replace('(^|\s)ma(\s|$)', '$1pa$2', 'ma ma ma ma'); Here the issue can be solved by using a 'lookahead': // Expect and get 'pa pa pa pa' echo preg_replace('(^|\s)ma(?=\s|$)', '$1pa', 'ma ma ma ma'); ---- Server IP: 69.147.83.197 Probable Submitter: 59.161.122.8 ---- Manual Page -- http://www.php.net/manual/en/function.preg-replace.php Edit -- https://master.php.net/note/edit/77822 Del: integrated -- https://master.php.net/note/delete/77822/integrated Del: useless -- https://master.php.net/note/delete/77822/useless Del: bad code -- https://master.php.net/note/delete/77822/bad+code Del: spam -- https://master.php.net/note/delete/77822/spam Del: non-english -- https://master.php.net/note/delete/77822/non-english Del: in docs -- https://master.php.net/note/delete/77822/in+docs Del: other reasons-- https://master.php.net/note/delete/77822 Reject -- https://master.php.net/note/reject/77822 Search -- https://master.php.net/manage/user-notes.php