title: Why list is unchanged?
body: <p>I had the following code: </p>
  
  <pre><code>s=['big','smas']
  s[-1]+'h'
  </code></pre>
  
  <p>My hope is to change <code>s</code> to be <code>['big','small']</code>. That code failed. So I changed the code to:</p>
  
  <pre><code>s=['big','smas']
  s[-1]=s[-1]+'h'
  </code></pre>
  
  <p>This works.
  I don't get why the first code is incorrect.</p>
  
  <p>In addition to <code>s[-1]=s[-1]+'h'</code>, is there any other way to change <code>s</code> to <code>['big','smash']</code>?</p>