title: Connecting list and sublist for accessing the related data
body: <p>I have the following list,</p>
  
  <pre><code>  mainlist=[10,20,30,40,50]
  </code></pre>
  
  <p>The following sublist which contains 6 numbers for each number in the first  list</p>
  
  <pre><code>sublist=[10,12,14,16,18,20,20,22,24,26,28,30,30,32,34,36,38,40,40,42,44,46,48,50,50,52,54,56,58,60]
  </code></pre>
  
  <p>Finally sublist1 which contains 5 numbers for each number in the first sublist.</p>
  
  <pre><code>[10,10.5,11,11.5,12,12,12.5,13,13.5,14,14,14.5,15,15.5,16,16,16.5,17,17.5,18,18,18.5,19,19.5,20,20,20.5,21,21.5,22,22,22.5,23,23.5,24,24,24.5,25,25.5,26,26.5,27,27.5,28,28,28.5,29,29.5,30,30,30.5,31,31.5,32,32,32.5,33,33.5,34,34.5,35,35.5,36,36,36.5,37,37.5,38,38.5,39,39.5,40,40,40.5,41,41.5,42,42,42.5,43,43.5,44,44,44.5,45,45.5,46,46,46.5,47,47.5,48,48,48.5,49,49.5,50,50,50.51,51.5,52,52.5,53,53.5,54,54.5,55,55.5,56,56,56.5,57,57.5,58,58.5,59,59.5,60]
  </code></pre>
  
  <p>How can I group them?, i.e when i choose value <code>10</code> in <code>mainlist</code> i should be able to see <code>10,12,14,16,18,20</code> from <code>sublist</code> and when i choose <code>10</code> in <code>sublist</code> i should be able to see the values <code>10,10.5,11,11.5,12</code> from <code>sublist1</code> and so on. Which data structure should be used for achieving this and how can i create that from these lists</p>
  
  <pre><code>10,20,30,40,50
  |
  --10,12,14,16,18,20
     |
     --10,10.5,11,11.5,12
  </code></pre>