如何在网址的后面消除反斜杠？

$url = \'http://www.example.com/example.php\';
$url = substr($url, 0, strrpos($url, \'.\'));
var_dump($url);
// output is: string(30) \"http://www.example.com/example\"

RewriteEngine On
RewriteBase /
# If the URL does not already exist as a file
RewriteCond %{REQUEST_FILENAME} !-f
# or directory
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^example$ /example.php [QSA,L,NC]