title: Sum a Nested List with condition in python
body: <p>In order to simplify the reading of information for all other users, I would like to reduce a nested list where names appear in duplicate.
  Concrete example:</p>
  <pre><code>[['savoielibrercgcm', '0.25'], ['MeriFer', '0.25'], ['XlassII', '0.25'], ['Tomixt_31', '0.25'], ['Tomixt_31', '0.25'], ['Tomixt_31', '0.25']]
  </code></pre>
  <p>(The value is not always equal to 0.25)</p>
  <p>The ideal would be to be able to add the content according to the nickname to obtain a list like this:</p>
  <pre><code>[['savoielibrercgcm', '0.25'], ['MeriFer', '0.25'], ['XlassII', '0.25'], ['Tomixt_31', '0.75']]
  </code></pre>
  <p>I could easily do it with a for loop and an if condition. But the program being heavy and having to manage data in great quantity, I would like to be able to &quot;optimize&quot; this code.
  I tried to go through a conversion to dict but that removes duplicate keys.</p>
  <p>Do you have any ideas ? of the map? I must admit that I have never touched the map() :/</p>
  <p>Thanks in advance for the help ^^'</p>