title: Python3 - Extracting data from a user inputted string. Could be in the wrong format
body: <p>I've been trying to find a way of taking a user input which should be in the form:
  [x<sub>1</sub>,y<sub>1</sub>][x<sub>2</sub>,y<sub>2</sub>]
  This whereby x<sub>1</sub>, x<sub>2</sub>, y<sub>1</sub>, y<sub>2</sub> are integer values.</p>
  
  <p>The point is in making a chess piece move from position <em>a</em> to position <em>b</em></p>
  
  <p>My aim is to have the user input it as so:</p>
  
  <pre><code>move = input("\nSyntax: '[x,y][x,y]'")
  </code></pre>
  
  <p>My intent is to break apart the string so that I end up with two lists.</p>
  
  <p>From = [x<sub>1</sub>,y<sub>1</sub>]</p>
  
  <p>To = [x<sub>2</sub>,y<sub>2</sub>]</p>
  
  <p>The nearest thing I found was: <em><a href="https://stackoverflow.com/questions/39138999/extract-the-data-specified-in-brackets-from-a-string-message-in-python">Extract the data specified in brackets '[ ]' from a string message in python</a></em>.</p>
  
  <p>However, for such a simple string in my case, I'm sure there's an easier way - what's most efficient. Also, in this case, the user may make a typo etc... How would I make sure it's in the format [x<sub>1</sub>,y<sub>1</sub>][x<sub>2</sub>,y<sub>2</sub>]?</p>