Question

I get stuck with a strange PHP behaviour after a cast. Here is the code :

$obj = new stdClass();
$obj->{'0'} = "test";

$array = (array)$obj;
var_dump($array);

This code will output :

array(1) { ["0"]=> string(4) "test" } 

Absolutely normal.

Now I add some code :

foreach ($array as $key => $value) {
   $array[$key] = strtoupper($value);
}
var_dump($array);

This code outputs :

array(2) {
  ["0"]=>
  string(4) "test"
  [0]=>
  string(4) "TEST"
}

Why my $key casted to int ?

If I try a simpler example :

$array = array("0" => "test");
foreach ($array as $key => $value) {
  $array[$key] = strtoupper($value);
}

var_dump($array);

This will output :

array(1) { [0]=> string(4) "TEST" }

Does somebody know why there is a cast of my $key to int ?

Update

I tried to force to cast my key to string :

$array["{$key}"] = $value;

and

$array[(string)$key] = $value;

But they are inserted as int. So my question should be : is there a way to insert keys as string into an array?

I know that I can solve my problem by using a second array and dismiss strings :

$obj = new stdClass();
$obj->{'0'} = "test";
$array = (array)$obj;
$array2 = array();
foreach ($array as $key => $value) {
  $array2[$key] = strtoupper($value);
}

But it would be nice to make it in a more beautiful way, conserving data type (and avoiding duplicating entries while iterating them as previously demonstrated).

Answer 1

@cHao found a clean and working solution to convert an object to an array without foreach() matters. My example becomes :

$array = array();
$obj = new stdClass();
$obj->{'0'} = "test";
foreach ($obj as $key => $value) {
   $array[$key] = strtoupper($value);
}

stdClass is iterable.

Thank you!