在PHP中检查json键的值

I have this function in php

我在php中有这个功能

<?php function showTable(){
$url = "https://10.0.0.1/lib/api/desk/branch/";

$params = array ("action" => "list","company_key" => "1");

$result=requestURL($url,$params);

$json_a=json_decode(strip_tags($result),true);

?>
<?p