title: Complexity of *in* operator in Python
body: <p>What is the complexity of the <code>in</code> operator in Python? Is it theta(n)?</p>
  <p>Is it the same as the following?</p>
  <pre><code>def find(L, x):
     for e in L:
         if e == x:
             return True
     return False
  </code></pre>
  <p><code>L</code> is a list.</p>