title: Python-Pandas: meaning of asterisk sign in expression
body: <p>While looking for a way to split a column into multiple columns within a loop, I stumbled upon <a href="http://www.swegler.com/becky/blog/2014/08/06/useful-pandas-snippets/" rel="nofollow">a list of useful Pandas snippets</a> containing this expression:</p>
  
  <pre><code> # Split delimited values in a DataFrame column into two new columns
  df['new_col1'], df['new_col2'] = zip(*df['original_col'].apply(lambda x: x.split(': ', 1)))
  </code></pre>
  
  <p>which works perfectly, but I am not able to understand how it operates, in particular with respect to the * sign. Until now, I have seen asterisks only in functions definitions and I have not been able to find any documentation for this case.</p>
  
  <p>Could anyone explain how it works?</p>