php正则如何在一个字符串中匹配一个数字答:str_arr[] = '1,11,21,35,41';str_arr[] = '1,5,15,21,35,41';str_arr[] = '1,5,';str_arr[] = '5';matche_arr = array();foreach($str_arr as $value){ if(preg_match('/(^|,)5(,|$)/',$value)){ matche_arr[] = $value;} } print_r($matche_arr);