title: Extract only relevant information from list of lists in python
body: <p>I have a list which has sub-lists of strings. </p>
  
  <p><strong>Like</strong>:</p>
  
  <pre><code>info = [['Price: 5000', 'In warranty', 'Weight: 8 kg'], 
  
  ['Refundable', 'Price: 2800', 'Weight: 5.5 kg', 'Extra battery power'], 
  
  ['Price: 9000', 'Non-exchangeable', 'Weight: 8 kg', 'High-Quality']..]
  </code></pre>
  
  <p>Every sub-list has some extra strings which are irrelevant. I only need exact 5 values in sub-lists that best describe info of the product and each of these 5 values have their own keywords.</p>
  
  <p><strong>What is the way to extract useful strings from sub-lists using keywords &amp; discard the rest?</strong> In above example I want to keep only '<strong>Price</strong>', '<strong>Weight</strong>'.</p>