[php] PHP preg_replace special characters

do this in two steps:

  1. replace not letter characters with this regex:

    [\/\&%#\$]

  2. replace quotes with this regex:

    [\"\']

and use preg_replace:

$stringWithoutNonLetterCharacters = preg_replace("/[\/\&%#\$]/", "_", $yourString);
$stringWithQuotesReplacedWithSpaces = preg_replace("/[\"\']/", " ", $stringWithoutNonLetterCharacters);