title: Get a random sample of a dict
body: <p>I'm working with a big dictionary and for some reason I also need to work on small random samples from that dictionary. How can I get this small sample (for example of length 2)? </p>
  
  <p>Here is a toy-model:</p>
  
  <pre><code>dy={'a':1, 'b':2, 'c':3, 'd':4, 'e':5}
  </code></pre>
  
  <p>I need to perform some task on dy which involves all the entries. Let us say, to simplify, I need to sum together all the values:</p>
  
  <pre><code>s=0
  for key in dy.key:
      s=s+dy[key]
  </code></pre>
  
  <p>Now, I also need to perform the same task on a random sample of dy; for that I need a random sample of the keys of dy. The simple solution I can imagine is</p>
  
  <pre><code>sam=list(dy.keys())[:1]
  </code></pre>
  
  <p>In that way I have a list of two keys of the dictionary which are somehow random. So, going back to may task, the only change I need in the code is:</p>
  
  <pre><code>s=0
  for key in sam:
      s=s+dy[key]
  </code></pre>
  
  <p>The point is I do not fully understand how dy.keys is constructed and then I can't foresee any future issue</p>