title: String substitution in Python 3?
body: <p>I'm trying to do something like this:</p>
  
  <pre><code>subs = 'world'
  "Hello {[subs]}"
  </code></pre>
  
  <p>in Python 3.</p>
  
  <p>I can't quite figure out the syntax (having come from Ruby/PHP). Am I missing something? The % operator in the docs I think is Python 2.x deprecated.</p>