title: python-graph derivative of a graph/data
body: <p>I have data and i can graph it using matplotlib. Now, is there a way to graph the derivative of that graph/data in python without importing any other modules? (I already have numpy and matplotlib)</p>
  
  <p>I do not have an equation for my data. The data is simply the times that a sensor was touched. I want to draw a graph that shows the rate at which the sensor was touched as time passes on (the derivative of the first graph). </p>