title: os.walk() not printing/accessing files
body: <p>I'm trying to use <em>os.walk</em> in order to access all files and all subfolders within a given folder. At first, my code looks like this:</p>
  
  <pre><code>for root, dirs, files in os.walk("/home/DataScience"):   
      for dirName in dirs:
            print dirName
  </code></pre>
  
  <p>However, the output of the above puts the <em>files</em> variable into a list-- I need it to iterate over each object within the list instead. </p>
  
  <p>So I go ahead and put in an additional <em>for</em> loop as such:</p>
  
  <pre><code>for root, dirs, files in os.walk("/home/DataScience"):   
      for dirName in dirs:
          for fileName in files:
              print dirName
  </code></pre>
  
  <p>Now, however, there is no output. For some reason, it seems as if putting the additional loop makes it such that the <em>print</em> statement on the 4th line doesn't output properly.</p>
  
  <p>My question then is this: why does this additional <em>for</em> loop eliminate my output?</p>