Why the key-value-pair won't be added?

<p>I'm trying to add a new key-value-pair at the end of every <code>users</code> element:</p><pre><br /><code><?php<br />$json = '[<br /> {<br /> "date": "2014-10-09T17:38:19Z",<br /> "users": [<br /> {<br /> "name": "Peter",<br /> "age": 20<br /> },<br /> {<br /> "name": "Anne",<br /> "age": 25<br /> },<br /> {<br /> "name": "William",<br /> "age": 30<br /> }<br /> ]<br /> }<br />]';<br /><br />addData ( $json );<br />function addData($json) {<br /> $obj = json_decode ( $json, true );<br /> foreach ( $obj as $items ) {<br /> foreach ( $items ['users'] as $users ) {<br /> $array = array (<br /> "myKey" => "myValue" <br /> );<br /> array_push ( $users, $array );<br /> }<br /> }<br /> $json = json_encode ( $obj );<br /><br /> echo $json;<br />}<br />?><br /></code><br /></pre><p>So the new <code>json</code> should look like</p><pre><br /><code>[ <br /> { <br /> "date":"2014-10-09T17:38:19Z",<br /> "users":[ <br /> { <br /> "name":"Peter",<br /> "age":20,<br /> "myKey":"myValue"<br /> },<br /> { <br /> "name":"Anne",<br /> "age":25,<br /> "myKey":"myValue"<br /> },<br /> { <br /> "name":"William",<br /> "age":30,<br /> "myKey":"myValue"<br /> }<br /> ]<br /> }<br />]<br /></code><br /></pre><p>Instead, I get my old <code>json</code> as an output, without the new key-value-pair.</p><br /><h2>Click here view more answers <a href="%20http://stackoverflow.com/questions/34470330/why-the-key-value-pair-wont-be-added">http://ift.tt/1mjgr9W</a></h2>