title: What does for x, *y in list mean in python
body: <p>I recently came across a piece of python code that looked like this</p>
  
  <pre><code>groups = {}
      for d, *v in dishes:
          for x in v:
              groups.setdefault(x, []).append(d)
  </code></pre>
  
  <p>dishes represents a 2d array.
  What does the 1st for loop statement mean?
  What is *v? What does the asterisk before v indicate?
  What other situations is an asterisk before a variable used?</p>