title: How do I uninstall all my python packages?
body: <p>I have previously had a good working version of Python 3.6.0 on my macOS Sierra, that included modules like <code>matplotlib</code>.</p>
  
  <p>However, I had the need of learning an image processing program, thus I wanted to learn openCV. I tried following <a href="http://www.pyimagesearch.com/2016/12/19/install-opencv-3-on-macos-with-homebrew-the-easy-way/#comment-425732" rel="nofollow noreferrer">this link</a> to download and install openCV. 
  In the process I have downloaded the following programs:</p>
  
  <ol>
  <li>Xcode</li>
  <li>Homebrew</li>
  <li>Python 2.7.10</li>
  <li>Python 3.6.1</li>
  </ol>
  
  <p>I found that I could import the cv2 module in my IDLE, however I could no longer import matplotlib in IDLE. Things are very messy with the 3 versions on Python on my macOS Sierra, and I would like to remove everything related to Python, so that I can start afresh, installing Python again, and hopefully install openCV on the same version of Python that has all the other modules that I was previously using. </p>