title: I would like php to "execute" a variable into a string
body: <p>I use JSON to organize my PHP code.</p>
  
  <p>I don't know if it's possible but I stocked inside of my Json a PHP variable.
  I would like to get it in my PHP script.</p>
  
  <p>I've created my JSON file : </p>
  
  <pre><code>{
      "link" : "?id=$org_id"
  }
  </code></pre>
  
  <p>In my php, I use the json_decode function.
  Then in PHP, I stock the result in a variable</p>
  
  <p>Thus,</p>
  
  <pre><code>$org_id = 456;
  echo $res; //output "?id=$org_id" while I wanted "?id=456"
  </code></pre>
  
  <p>What can I do?</p>