PHP secondary array conversion json

<code>json_encode(<span>$param_array</span>);</code>

<code>{
    <span>"appid"</span>: <span>"1500001105"</span>,
    <span>"nonce"</span>: <span>32490</span>,
    <span>"timestamp"</span>: <span>1458195253</span>,
    <span>"signature"</span>: <span>"bf13fe77f46a96edba1a0e2b84fce66580b2f50b"</span>,
    <span>"param"</span>: {
        <span>"userid"</span>: <span>"bonnie"</span>
    }
}</code>

<code><span>$param</span> = <span>array</span>(
    <span>'userid'</span>=><span>'bonnie'</span>
);
<span>$params</span> = <span>array</span>(
    <span>'appid'</span>=><span>'1500001105'</span>,
    <span>'nonce'</span>=><span>$nonce</span>,
    <span>'timestamp'</span>=><span>$timestamp</span>,
    <span>'signature'</span>=><span>$signature</span>,
    <span>'param'</span>=><span>$param</span>,
);
<span>$params_json</span> = json_encode(<span>$params</span>);</code>