title: How to subtract values from dictionaries
body: <p>I have two dictionaries in Python:</p>
  
  <pre><code>d1 = {'a': 10, 'b': 9, 'c': 8, 'd': 7}
  d2 = {'a': 1, 'b': 2, 'c': 3, 'e': 2}
  </code></pre>
  
  <p>I want to substract values between dictionaries d1-d2 and get the result:</p>
  
  <pre><code>d3 = {'a': 9, 'b': 7, 'c': 5, 'd': 7 }
  </code></pre>
  
  <p>Now I'm using two loops but this solution is not too fast</p>
  
  <pre><code>for x,i in enumerate(d2.keys()):
          for y,j in enumerate(d1.keys()):
  </code></pre>