title: Saving list of lists into another list of list but with changes in python
body: <p>i have a list like this one :</p>
  
  <pre><code>list1= [['Sarah', 55, 7, 'x'], ['John', 24, 8, 'x']]
  </code></pre>
  
  <p>and i want to copy it to another list but keeping it as a matrix like that :</p>
  
  <pre><code>list2= [['Sarah', 55.0, 7.0], ['John', 24.0, 8.0]]
  </code></pre>
  
  <p>so what i want to do is making every number a float and deleting the last element of every sub-list</p>