title: How to slice pandas DataFrame by disjunction statement (logical "or")?
body: <p>I would like to slice a <code>pandas.DataFrame</code> which satisfies condition A <strong>or</strong> condition B. Most of the search results only show how to slice dataframe using <strong>"and"</strong>. So I wonder if it is possible to use <strong>"or"</strong> operator without converting (A and B) to (not (not A and not B))? Because sometimes there are many "or" conditions needed, and converting might be troublesome.</p>
  
  <p>I tried to use:</p>
  
  <pre><code>df[(df['c1']==x1) or (df['c2']==x2)]
  </code></pre>
  
  <p>but it does not work.</p>