How to generate hierarchy with json and php?

Question

How to generate a hierarchy with json and php like the image below?

Answer 1

You can try this

Array:

$arr = array(
    "X1" => array(
        "X2" => array("X4", "X5"),
        "X3" => array("X6", "X7")
    )
);

JSON Encode:

echo $json = json_encode($arr); //{"X1":{"X2":["X4","X5"],"X3":["X6","X7"]}}