What's json syntax for {"data":"w-file1","attr":{"rel":"file"}} in php?

What would be php code to get this json?

开发者_StackOverflow社区{  "data": "w-file1",
   "attr": { "rel" : "file"}
}

I am getting PHP Parse error: syntax error, unexpected T_DOUBLE_ARROW error for

$file = ("data" => "w-file1","attr" => ("rel" => "file"));
echo json_encode($file);

$file needs to be an array as does the attr key:

$file = array("data" => "w-file1","attr" => array("rel" => "file"));
echo json_encode($file);

Of course, you could inline it:

echo json_encode(array("data" => "w-file1","attr" => array("rel" => "file")));

Or, there is the OOP approach:

$file = new stdClass();
$file->data = 'w-file';
$file->attr = new stdClass();
$file->attr->rel = "file";
echo json_encode($file);

You need to specify array for $file and attr:

$file = array("data" => "w-file1","attr" => array("rel" => "file"));
echo json_encode($file);

$file = array(
    "data" => "w-file1",
    "attr" => array("rel" => "file")
);
echo json_encode($file);