PHP array with numeric keys as string can't be used [duplicate]

Question

I have a PHP array that has numeric keys as a string type.

But when I try and access them PHP is giving me an undefined index error.

$a = (array)json_decode('{"1":1,"2":2}'); var_dump($a); var_dump(isset($a[1])); var_dump(isset($a["1"])); var_dump($a[1]); var_dump($a["1"]); 

Output:

 array (size=2)     '1' => int 1     '2' => int 2  boolean false  boolean false  ERROR: E_NOTICE: Undefined offset: 1  null  ERROR: E_NOTICE: Undefined offset: 1  null 

How do I access these values?

Demo: http://codepad.viper-7.com/8O03IM

Answer 1

So, I haven't seen any other answers touch upon this, but @xdazz came close.

Let's start our environment, $obj equals the object notation of a decoded string:

php > $obj = json_decode('{"1":1,"2":2}');  php > print_r($obj); stdClass Object (     [1] => 1     [2] => 2 )  php > var_dump( $obj ); object(stdClass)#1 (2) {   ["1"]=>   int(1)   ["2"]=>   int(2) } 

If you want to access the strings, we know the following will fail:

php > echo $obj->1;  Parse error: parse error, expecting `T_STRING' or `T_VARIABLE' or `'{'' or `'$'' in php shell code on line 1 

Accessing the object variables

You can access it like so:

php > echo $obj->{1}; 1 

Which is the same as saying:

php > echo $obj->{'1'}; 1 

Accessing the array variables

The issue with arrays is that the following return blank, which is the issue with typecasting.

php > echo $obj[1]; php > 

If you typecast it back, the object is once again accessible:

php > $obj = (object) $obj; php > echo $obj->{1}; 1 

Here is a function which will automate the above for you:

function array_key($array, $key){     $obj = (object) $array;     return $obj->{$key}; } 

Example usage:

php > $obj = (array) $obj; php > echo array_key($obj, 1); 1  php > echo array_key($obj, 2); 2