The "asort()" function used to sorting an array elements by the values and keep the original keys.

     asort(array,sorttype)

In the above syntax "array" is the array to be sorted, "sorttype" specifies the method to be used for sorting, it can have values "SORT_REGULAR" for default, "SORT_NUMERIC" treat values numerically, "SORT_STRING" treat values as strings,"SORT_LOCALE_STRING" treat values as strings based on local settings .

    <?php
    $b=array("1"=>"Grapes","2"=>"Apple","3" =>"Cherry");
    asort($b);
    print_r($b);
    ?>

    Array
     {
      [2] => Apple
      [3] => Cherry
      [1] => Grapes
     }

In the above example all the elements of the array "$b" is sorted using the default type "SORT_REGULAR" based on the values and the keys remain the same.