title: comparing dicts based on key and create a new dict with the missing key, with a 0 value in python3
body: <p>I have three dicts say <code>dict_a</code>, <code>dict_b</code> and <code>dict_c</code></p>
  
  <pre><code>dict_a={'key1':a, 'key2':b, 'key3':c}
  dict_b={'key1':a, 'key2':b, 'key4':d}
  dict_c={'key3':c, 'key1':a, 'key5':e}
  </code></pre>
  
  <p>Here the keys that are represented overall are: key1, key2, key3, key4, key5 with their respective values. </p>
  
  <p>What I am looking for is eg., to create a new dict (or keep the dicts) and fill the missing keys in each dict in compare to the overall keys with 0 values and the key e.g,:</p>
  
  <pre><code>dict_a={'key1':a, 'key2':b, 'key3':c, 'key4':0, 'key5':0}
  dict_b={'key1':a, 'key2':b, 'key3':0, 'key4':d, 'key5':0}
  dict_c={'key1':a, 'key2':b, 'key3':c, 'key4':0, 'key5':e}
  </code></pre>
  
  <p>I am experienced in C, and based on my "limited knowledge" in python I would run a nested for-loop with a bunch of if, else statement to solve this, however what I know is python have some tools eg. <code>zip</code>, <code>lamda</code> etc. to nail this in a simple way. But I don't know how to start and begin, or even if there is a library that can solve this ?</p>
  
  <p>it doesen't matter if I create new dicts with the missing keys or simple replace the existing dict, both are usable.</p>