php中array_diff()函数比较数组差异的三种实现方法

function fun($arr_1,$arr_2)
{
       foreach ($arr_1 as $key => $val)
      {
              $bool = false;
              foreach ($arr_2 as $k => $v)
             {
                   if($bool = ($val == $v))
                  {
                           break;
                   }
             }
             if(!$bool)
            {
                 $diff[$key] = $val;
             }
       }
}

foreach ($arr_1 as $key => $val)
{
    if(in_array($val,$arr_2))
    {
            unset($arr_1[$key]);
    }
}

$arr_2 = array_flip($arr_2);
foreach ($arr_1 as $key => $val)
{
    if(isset($arr_2[$val]))
    {
            unset($arr_1[$key]);
    }
}