title: Python matplotlib plot /graph partial refresh from starting point
body: <p>Sorry I am a bit new to python and matplotlib so I dont know if I am asking it correctly. As of now I am plotting graphs where I collect an array of integers coming via serial port and refreshing the whole plot area at once. Now I want to do partial refresh (idk if it is the correct word) something like a PPG/ECG trace where once the line/trace reaches the end of plot area it starts from beginning, something like in the example here
  [1]: <a href="http://theblogofpeterchen.blogspot.com/2015/02/html5-high-performance-real-time.html" rel="nofollow noreferrer">http://theblogofpeterchen.blogspot.com/2015/02/html5-high-performance-real-time.html</a>.
  I do understand that if I keep on appending the serial port data and plotting it as soon as it arrives will keep on extending the plot forward but I have no clue how to return back at the the beginning point and redraw it gradually as in ECG.</p>
  <p>Kindly help in this regard</p>
  <p>Thank you</p>