title: Use a list of item and list of indices as a reference to index other lists
body: <p>If I have two lists, one with all possible items and one with indices for those items. For instance lets say The first list is all the 26 alphabet and the other list is sequence of 26 numbers from 100 to 2600 with 100 increment.</p>
  <pre><code>alpha = [&quot;A&quot;, &quot;B&quot;, &quot;C&quot;, &quot;D&quot;, &quot;E&quot;, ......., &quot;X', &quot;Y&quot;, &quot;Z&quot;]
  idx = [100, 200, 300, 400, 500, ......., 2400, 2500, 2600]
  
  </code></pre>
  <p>Now I want to use these two lists as a reference to index any list of letters I come across. Here is an example of what I want to achieve.</p>
  <pre><code>Given :
  l = [&quot;A&quot;, &quot;A&quot;, &quot;Q&quot;, &quot;K&quot;]
  
  Output:
  
  lx = [100, 100, 1700, 1100]
  </code></pre>
  <p>Another example</p>
  <pre><code>Given :
  l = [&quot;E&quot;, &quot;R&quot;, &quot;I&quot;, &quot;N&quot;, &quot;W&quot;, &quot;A&quot;, &quot;L&quot;, &quot;T&quot;, &quot;E&quot;, &quot;R']
  
  Output:
  
  lx = [500, 1800, 900, 1400, 2300, 100, 1200, 2000, 500, 1800]
  </code></pre>
  <p>I tried different ways like map() with no luck</p>