title: How to install cv2?
body: <p>My environment:
  Ubuntu 18.0.4 LTS (also tried on 19.04)</p>
  
  <p>I use/need python3 (3.6.8 installed)</p>
  
  <p>I need cv2, which is a model of opencv.</p>
  
  <p>I tried several receipts I found on the Internet, but nothing worked.</p>
  
  <p>I tried to install as pre-compiled (sudo apt-get install python-opencv) - No error, but when I try the test:</p>
  
  <pre><code>import cv2 as cv
  print(cv.__version__)
  </code></pre>
  
  <p>I get error module not found.</p>
  
  <p>The problem seems that I have installed also anaconda. The above test uses then anaconda, and cannot find the module.</p>
  
  <p>Compiling from source installed for python2, but I do need python3. (The test also uses anaconda)</p>
  
  <p>One of my receipts worked till the end, but with the line:</p>
  
  <pre><code>workon OpenCV-master-py3
  </code></pre>
  
  <p>It gaves me the error workon not found.</p>
  
  <p>I tried then to install via Conda, but that wants to downgrade Conda. </p>
  
  <p>Is there a way to run it without anaconda and find a replacement for 
  "workon  OpenCV-master-py3"</p>