title: Python using open (w+) FileNotFoundError
body: <p>I get a <code>FileNotFoundError</code> when trying to write to a file.
  This is my code:</p>
  <pre><code>def save_txt_individual_tracks(track, folder, i):
      f = open(folder+str(i)+'.txt','w+')
          for line in track:
              l=str(line[0])+','+str(line[1])+','+str(line[2])+'\n'
          f.write(l)
      f.close()
  </code></pre>
  <p>Which I call like so:</p>
  <pre><code>save_txt_individual_tracks(new,'E:/phoneTracks/'+track_name+'/',i)
  </code></pre>
  <p>Which gives me this error:</p>
  <blockquote>
  <p>FileNotFoundError: [Errno 2] No such file or directory: 'E:/phoneTracks/TA92903URN7ff/0.txt'</p>
  </blockquote>
  <p>I created folder <code>phoneTracks</code> in E. And I am confused about <code>open()</code> with mode <code>'w+'</code>, which is used to create a new file. Why do I get a <code>FileNotFoundError</code>? What can I do to fix it?</p>
  <p>I am running python3.4.3 on windows 7</p>