title: Data analysis on .json file in Python
body: <p>I have to analyse a .json file which looks like this:</p>
  
  <pre><code>{"columns":["id","timestamp","offset_freq","reprate_freq"],
  "index":[0,1,2,3,4,5,6,7 ... 
  "data":[[526144,1451900097533,20000000.495000001,250000093.9642499983],[...    }
  </code></pre>
  
  <p>it has over 600000 indexes so I dont want to show you the whole file.</p>
  
  <p>I have found out that I can read the file simply by:</p>
  
  <pre><code>df = pd.read_json(file_name_or_Python_string, orient='split')
  </code></pre>
  
  <p>But what do I do now if I want to do some math on one of the columns?
  For example devide all the offset_freq by 2?</p>