title: How to sort a list of lists (non integers)?
body: <p>I have a list of lists that looks like this:</p>
  
  <pre><code>[['10.2100', '0.93956088E+01'],
   ['11.1100', '0.96414905E+01'],
   ['12.1100', '0.98638361E+01'],
   ['14.1100', '0.12764182E+02'],
   ['16.1100', '0.16235739E+02'],
   ['18.1100', '0.11399972E+02'],
   ['20.1100', '0.76444933E+01'],
   ['25.1100', '0.37823686E+01'],
   ['30.1100', '0.23552237E+01'],...] 
  </code></pre>
  
  <p>(here it looks as if it is already ordered, but some of the rest of the elements not included here to avoid a huge list, are not in order)<br>
  and I want to sort it by the first element of each pair, I have seen several very similar questions, but in all the cases the examples are with integers, I don't know if that is why when I use the <code>list.sort(key=lambda x: x[0])</code> or the sorter, or the version with the <code>operator.itemgetter(0)</code> I get the following:</p>
  
  <pre><code>[['10.2100', '0.93956088E+01'],
   ['100.1100', '0.33752517E+00'],
   ['11.1100', '0.96414905E+01'],
   ['110.1100', '0.25774972E+00'],
   ['12.1100', '0.98638361E+01'],
   ['14.1100', '0.12764182E+02'],
   ['14.6100', '0.14123326E+02'],
   ['15.1100', '0.15451733E+02'],
   ['16.1100', '0.16235739E+02'],
   ['16.6100', '0.15351242E+02'],
   ['17.1100', '0.14040859E+02'],
   ['18.1100', '0.11399972E+02'], ...]
  </code></pre>
  
  <p>apparently what is doing is sorting by the first character appearing in the first element of each pair.</p>
  
  <p>Is there a way of using <code>list.sort</code> or <code>sorted()</code> for ordering this pairs with respect to the first element?</p>