title: Parse JSON with PHP and output to CSV
body: <p>I'm wondering how I can use PHP to parse the JSON below and output the parsed values into CSV format. </p>
  
  <pre><code>{
   "test":{"12345":"98765","56789":"54321"},
   "control":{"99999":"98765","88888":"98765"}
  }
  </code></pre>
  
  <p>I would like to extract just the keys from the <code>test</code> array (i.e. <code>12345</code>, <code>56789</code>) and have them returned in CSV format. Is that possible to do using json_decode?</p>
  
  <p>Please feel free to ask any questions if you need more information</p>