title: Python: Filter positive and negative integers from string
body: <p>Python 3:
  Given a string (an equation), return a list of positive and negative integers.
  I've tried various regex and list comprehension solutions to no avail.</p>
  
  <p>Given an equation 4+3x or -5+2y or -7y-2x
  Returns: [4,3], [-5,2], [-7,-2]</p>
  
  <p>input</p>
  
  <pre><code>str = '-7y-2x'
  </code></pre>
  
  <p>output</p>
  
  <pre><code>my_list = [-7, -2]
  </code></pre>