怎么判断两组字符串是否有相同的字符

$a = '2344';
$d = array('12', '22', '234', '324', '4432', '4444');
$a = count_chars($a, 1);
foreach($d as $b) {
  $t = count_chars($b, 1);
  $f = 0;
  if(array_keys(array_intersect_key($t, $a)) == array_keys($a)) $f = 1;
  printf("b = %s %s\n", $b, $f ? '真' : '假');
}

b = 12 假
b = 22 假
b = 234 真
b = 324 真
b = 4432 真
b = 4444 假

$a='5415';
$a=str_split($a);
$a=array_count_values($a);
$b='514';
$b=str_split($b);
$b=array_count_values($b);
$result=true;
foreach($b as $k=>$v){
    if(!isset($a[$k]) OR $a[$k]<$v){
        $result=false;
        break;
    }
}
var_dump($result);