PHP JSON Error: Cannot use object of type stdClass as array Solution

When php calls json_decode again to generate an json object from a string object, if you use the [] operator to fetch data, you get the following error:

Cannot use object of type stdClass as array

$res = json_decode($res);

$res['key']; // Put  json_decode()  Use the object after as an array. 

Solutions (2 kinds):

1. Use json_decode ($d, true). Is to set the second variable of json_decode to true.
2. json_decode ($res) returns an object that cannot be accessed using $res ['key']. Instead, $res- > key will do.