Description:
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Associative Arrays loose their "string-but-numbers-only-keys" when being merged.

array_something["34"]="hello 34";
will get lost when being array_merged.

array_something["34_ID"]="hello 34";
will be ok when being array_merged.

I know this is most likely a feature, but it really did threw me off and took a while to get down to. To me this is an unwanted behavior.

Even more so, as you cannot force the array to remain associative, even not by "(string)" or settype, as you can see in the demo-code. 

Thank you!
Tobias Gassmann


Reproduce code:
---------------
$array_one=array();
$array_one["one"]   = "Database-Entry with UID='one'";
$array_one["2_uid"] = "Database-Entry with UID='2_uid'";
$array_one["ID_3"]  = "Database-Entry with UID='ID_3'";
print_r($array_one);

$array_two=array();
$array_two["four"]  = "Database-Entry with UID='four'";
$array_two["5"]     = "Database-Entry with UID='5'";
$string_six="6";
$array_two["$string_six"] = "Database-Entry with UID='6'";
$string_seven="7";
settype($string_seven,"string");
$array_two["$string_seven"] = "Database-Entry with UID='7'";
$array_two["ID_8"]  = "Database-Entry with UID='ID_8'";
print_r($array_two);

$array_three = array_merge($array_one,$array_two);
print_r($array_three);


Expected result:
----------------
I would have expected for all keys to remain what they are. 

Actual result:
--------------
The keys "5", "6" and "7" got lost, although I declared them as strings.