title: How to extract multiple JSON objects from one file?
body: <p>I am very new to Json files. If I have a json file with multiple json objects such as following:</p>
  
  <pre class="lang-json prettyprint-override"><code>{"ID":"12345","Timestamp":"20140101", "Usefulness":"Yes",
   "Code":[{"event1":"A","result":"1"},…]}
  {"ID":"1A35B","Timestamp":"20140102", "Usefulness":"No",
   "Code":[{"event1":"B","result":"1"},…]}
  {"ID":"AA356","Timestamp":"20140103", "Usefulness":"No",
   "Code":[{"event1":"B","result":"0"},…]}
  …
  </code></pre>
  
  <p>I want to extract all "Timestamp" and "Usefulness" into a data frames:</p>
  
  <pre class="lang-none prettyprint-override"><code>    Timestamp    Usefulness
   0   20140101      Yes
   1   20140102      No
   2   20140103      No
   …
  </code></pre>
  
  <p>Does anyone know a general way to deal with such problems?</p>