php怎么截取逗号之前的字符

$str='aaaaa,bbbbbbb,ccccc';<br />if(strpos($str,',')){<br />	preg_match('/([^,]+?),/i',$str,$match);<br />}<br /><br />print_r($match[1]);<br />/*<br />aaaaa<br />*/

$s = 'aaaaa,bbbbbbb,ccccc';<br />echo strtok($s, ',');

$string = '111a,111';<br />            $flag = strpos($string, ',');<br />            if($flag !== FALSE){<br />                $arr = explode(',', $string);<br />                echo $arr[0];<br />            }else{<br />                echo $string;<br />            }