$ar1 = array("color"=> array("favorite"=>"red","name"=>"test"));
$ar2 = array("color"=> array("favorite"=>"green","code"=>"code"));
print_r (array_merge ($ar1, $ar2));
print_r(array_merge_recursive ($ar1, $ar2));

/**
 * @Author:   HTL
 * @Description: 根据指定的健名将$ar2中的所有健值复制到$ar1对应的健值中
 * @Return：$ar1
 */
 function array_more_merge($ar1,$ar2,$key_name){
  if(
    !$ar1
    || !is_array($ar1)
    || count($ar1)<=0
    || !$ar2
    || !is_array($ar2)
    || count($ar2)<=0
    || !$key_name
    || strlen($key_name)<=0)
  {
    return $ar1;
  }
  /*不能使用for进行循环,因为如果数组中的索引不是连续的则使用for可能无法正确的完成循环
  如 $a =
      Array(
      1 => Array("id" => 1 )
      ,8 => Array("id" => 2 )
      ,4 => Array("id" => 4 )
     );
  该数组数为3所以只能找到[1],而[8][4]在循环中不会进行处理,因为$i <=count($a)不成立<br>　　*/
  for ($i=0; $i <=count($a) ; $i++) {
      print_r($a[$i]);
  }
  foreach ($ar1 as $i=>$items) {
    foreach ($ar2 as $key=>$item) {
      if($ar2[$key][$key_name]==$ar1[$i][$key_name]){
        $keys = array_keys($ar2[$key]);
        foreach ($keys as $name) {
          $ar1[$i][$name] = $ar2[$key][$name];
        }
      }
    }
  }
  return $ar1;
}
$ar1 = '{"1":{"cost":"1","id":"1","total_price":"5"},"2":{"cost":"2","id":"2","total_price":"10"},"4":{"cost":"4","id":"4","total_price":"20"}}';
$ar1 = json_decode($ar1,true);
$ar2 = '{"1":{"cost":"1","id":"1","total_price":"5"},"2":{"cost":"20","id":"2","total_price":"100"},"4":{"cost":"40","id":"4","total_price":"200"}}';
$ar2 = json_decode($ar2,true);
echo "array_merge_recursive:";
print_r(array_merge_recursive($ar1,$ar2));
echo "array_merge:";
print_r(array_merge($ar1,$ar2));
echo "array_more_merge:";
print_r($this->array_more_merge($ar1,$ar2,"id"));
die();