php排除字符串里包含某字符,该如何处理

$a = "'你好.你好','你好啊ct','他好','他好啊','我好','我好啊'";

$a = "'你好.你好','你好啊ct','他好','他好啊','我好','我好啊'";
$b=explode(',',$a);
$c = array(".", "ct");
foreach($b as $value){
     foreach($c as $v){
	     if(strpos($value,$v) !==false){ 
		    $ar[]=$value;
			break;
		 }	
	 }
}
$result = array_diff($b, $ar);
echo join(',',$result);

 
$a = "'你好.你好','你好啊ct','他好','他好啊','我好','我好啊'";
$b=explode(',',$a);
$c = array(".", "ct");   
 foreach($c as $v){
	     $p="/" .preg_quote($v) ."/";
	     $ar[]=array_values(preg_grep($p,$b));  	
	 }
foreach($ar as $v) $arr[]=$v[0];
$result=array_diff($b,$arr);
echo join(',',$result);