note 101417 added to language.expressions

I wanna replace some undesirable characters on a string, the code witch i wrote doesn’t work, can you help please? The code is: for ($i=0;$i<strlen($content);$i++) { $caractere=$content[$i]; $ascii=ord($caractere); if(!(48 <= $ascii <= 57) && !(64 <= $ascii <= 90) && !(96 <= $ascii <= 122) && !(128 <= $ascii <= 154) && !(160 <= $ascii <= 165) && ($ascii != 173)) { $content[$i]=" "; } } echo $content; ---- Server IP: 69.147.83.197 Probable Submitter: 196.12.232.146 ---- Manual Page -- http://www.php.net/manual/en/language.expressions.php Edit -- https://master.php.net/note/edit/101417 Del: integrated -- https://master.php.net/note/delete/101417/integrated Del: useless -- https://master.php.net/note/delete/101417/useless Del: bad code -- https://master.php.net/note/delete/101417/bad+code Del: spam -- https://master.php.net/note/delete/101417/spam Del: non-english -- https://master.php.net/note/delete/101417/non-english Del: in docs -- https://master.php.net/note/delete/101417/in+docs Del: other reasons-- https://master.php.net/note/delete/101417 Reject -- https://master.php.net/note/reject/101417 Search -- https://master.php.net/manage/user-notes.php