php过滤表情符号

<?php 
        $clean_text = "";
// Match Emoticons
        $regexEmoticons = '/[x{1F600}-x{1F64F}]/u';
        $clean_text = preg_replace($regexEmoticons, '', $str);
// Match Miscellaneous Symbols and Pictographs
        $regexSymbols = '/[x{1F300}-x{1F5FF}]/u';
        $clean_text = preg_replace($regexSymbols, '', $clean_text);
// Match Transport And Map Symbols
        $regexTransport = '/[x{1F680}-x{1F6FF}]/u';
        $clean_text = preg_replace($regexTransport, '', $clean_text);
// Match Miscellaneous Symbols
        $regexMisc = '/[x{2600}-x{26FF}]/u';
        $clean_text = preg_replace($regexMisc, '', $clean_text);
// Match Dingbats
        $regexDingbats = '/[x{2700}-x{27BF}]/u';
        $clean_text = preg_replace($regexDingbats, '', $clean_text);
        return $str;