如何向现有 JSON-PHP 插入新键值

Question

I have been searching online for the past 2 hours and couldn't find an answer. I have some data stored in my database in JSON format. I want to add a new key and value to the json data. Example

{
    "systemService":"1234",
    "DATA_PLAN":"SMEF",
    "amount":"5000"
}


$message = .$name "" .$post;

I want to add a new key and value to it. "message":$message

to something like this.

{
    "systemService":"1234",
    "DATA_PLAN":"SMEF",
    "amount":"5000"
    "message":"mike accountance"
}

How do I go about it in PHP

Answer 1

Here is an example how you can do it:

Method 1 decoding it to an associative array:

$object = json_decode('{
        "systemService":"1234",
        "DATA_PLAN":"SMEF",
        "amount":"5000"
    }', true);
    
$object['message'] = "Your message";
    
echo json_encode($object); //this will give you the json string with your new property

Method 2 decoding it to an object:

$object = json_decode('{
        "systemService":"1234",
        "DATA_PLAN":"SMEF",
        "amount":"5000"
    }');
    
$object->message = "Your message";
    
echo json_encode($object); //this will give you the json string with your new property

Answer 2

You could convert the JSON string to object (with PHP json_decode function), add the new property, then convert it back to string (with PHP json_encode function), ie :

$str = '{
  "systemService": "1234",
  "DATA_PLAN": "SMEF",
  "amount": "5000"
}';
$obj = json_decode($str);
$obj->message = 'mike accountance';
$str = json_encode($obj);
echo $str;