Download files from a list if not already downloaded
<p>I can do this in c#, and the code is pretty long.  </p>

<p>Would be cool if someone can show me how this would be done via python.</p>

<p>Pseudo code is:</p>

<pre><code>url: www.example.com/somefolder/filename1.pdf

1. load file into an array (file contains a url on each line)
2. if file e.g. filename1.pdf doesn't exist, download file
</code></pre>

<p>The script can be in the following layout:</p>

<pre><code>/python-downloader/
/python-downloader/dl.py
/python-downloader/urls.txt
/python-downloader/downloaded/filename1.pdf
</code></pre>
