title: Creating a list of missing files after reading paths from another list
body: <p>I have a list of file paths <code>listt</code>:</p>
  
  <pre><code>['/data0/river_routes.nc',
   '/dat/rho0_profile.nc',...]
  </code></pre>
  
  <p>I want to check if they exist, and if not - create a list <code>list1</code> with just the paths of the missing files.</p>
  
  <p>I can create <code>list1</code> full of <code>True/False</code> using:</p>
  
  <pre class="lang-py prettyprint-override"><code>import os,time
  list1 = []
  for file in listt:
      list1.append(os.path.isfile(file))
  </code></pre>
  
  <p>But I'm not sure how to create a list of the missing paths in the most efficient way</p>