PHP's Object Notation: Accessing Fields/Members With Hyphens in Their Name

Here's another quick tip; I fought through this issue today at work.  In PHP, you might have a need to parse some JSON that contains a field/member name with one or more hyphens.  Here's an example:

{
  "field-one" : 1,
  "field-two" : 2,
  "field-three" : [ 1, 2, 3 ]
}

Most JSON libraries should convert this JSON string into a native object with ease.  However, in PHP when you try to access $obj->field-one directly, PHP will complain given the hyphen in the member name.  The solution to this simple problem, is to wrap the name in curly braces, like so:

$obj->{'field-one'}

Here's a more complete example using Services_JSON in PHP:

<?php

require_once("JSON.php");
$json = new Services_JSON();

$string = "{\"field-one\":1,\"field-two\":2," .
                "\"field-three\":[1,2,3]}";

$obj = $json->decode( $string );

// Will FAIL
//echo $obj->field-one;

// WORKS
echo $obj->{'field-one'};

?>

For your download convenience, you can find the latest Services_JSON library here (as of 4/22/09).  The official PEAR CVS repository for Services_JSON can be found here.  Enjoy.