合并具有相同键的数组，array_merge_recursive无法正常工作

Question

I've two arrays with ids as key and some fields and I would like to merge them but I don't understand why it doesn't work, here is my example code:

$Podcasts1 = array("1234" => array('title' => "myTitle", "type" => "myType"));
$Podcast2 = array("1234" => array("content" => "myContent"));
$podcasts = array_merge_recursive($Podcasts1, $Podcast2);
var_dump($Podcasts1, $Podcast2, $podcasts);

There is the result:

array:1 [▼
  1234 => array:2 [▼
    "title" => "myTitle"
    "type" => "myType"
  ]
]
array:1 [▼
  1234 => array:1 [▼
    "content" => "myContent"
  ]
]
array:2 [▼
  0 => array:2 [▼
    "title" => "myTitle"
    "type" => "myType"
  ]
  1 => array:1 [▼
    "content" => "myContent"
  ]
]

And there is the result I woulk like to have:

array:[
1234 => array(
        "title" => "myTitle"
        "type" => "myType"
        "content" => "myContent")
]

I don't understand why the code given on PHP.net work and mine doesn't

Code:

$ar1 = array("color" => array("favorite" => "red"), 5);
$ar2 = array(10, "color" => array("favorite" => "green", "blue"));
$result = array_merge_recursive($ar1, $ar2);

Result:

Array
(
    [color] => Array
        (
            [favorite] => Array
                (
                    [0] => red
                    [1] => green
                )

            [0] => blue
        )

    [0] => 5
    [1] => 10
)

Answer 1

Change the key 1234 to string like

 $Podcasts1 = array('a' => array('title' => "myTitle", "type" => "myType"));
 $Podcast2 = array('a' => array("content" => "myContent"));
 $podcasts = array_merge_recursive($Podcasts1, $Podcast2);
 var_dump($Podcasts1, $Podcast2, $podcasts);

array_merge_recursive works on string keys.

Answer 2

It wont work for numeric key as function description says

If the input arrays have the same string keys, then the values for these keys are merged together into an array, and this is done recursively, so that if one of the values is an array itself, the function will merge it with a corresponding entry in another array too. If, however, the arrays have the same numeric key, the later value will not overwrite the original value, but will be appended.

Ref Link