title: Python placeholders in strings containing the % symbol
body: <p>I want to be able to use a placeholder in a string that already contains a <code>%</code> symbol. For instance, I would like to be able to iterate to open multiple URLs by my URL already contains a <code>%</code> symbol, example url: </p>
  
  <pre><code>http://www.example.com/BLABLA%123BLABLApage=1
  </code></pre>
  
  <p>To do so, I want to replace the number 1 by a placeholder (<code>%d</code>), but the code seems to be confused by the presence of the <code>%</code> that comes before the placeholder.</p>