title: Extract index of Non duplicate elements in python list
body: <p>I have a list:</p>
  
  <pre><code>input = ['a','b','c','a','b','d','e','d','g','g']
  </code></pre>
  
  <p>I want index of all elements except duplicate in a list.</p>
  
  <pre><code>output = [0,1,2,5,6,8]
  </code></pre>