title: Removing keys from dictionary by specifying only a part of key
body: <p>Python 3:<br></p>
  
  <p>Suppose I have a dictionary:</p>
  
  <pre><code>d={aaa0:'Hello',aaa1:'how',bbb0:'are',bb1:'you'}
  </code></pre>
  
  <p>Now how can I remove all the keys that contain 'a' in keys? I know how to remove keys by specifying each key and then deleting it. <br></p>
  
  <p>I want to know if there is any "pythonic" way to remove keys by specifying just the part of the key.<br>
  Like:<br></p>
  
  <pre><code>if d['contains a'] del[key]
  </code></pre>
  
  <p>something like that.</p>
  
  <p>Expected Output:</p>
  
  <pre><code>d={bbb0:'are',bb1:'you'}
  </code></pre>