title: How to read contents of a large csv file and write them to another file with an operator in Python?
body: <p>I have a csv file of data from a LiDAR sensor that looks like this, but with a bagillion more lines:</p>
  
  <pre><code>scan_0,scan_1,scan_2
  timestamp_0,timestamp_1,timestamp_2
  7900200,7900225,7900250
  logTime_0,logTime_1,logTime_2
  27:46.8,27:46.8,27:46.8
  distance_0,distance_0,distance_0
  132,141,139
  136,141,155
  139,141,155
  138,143,155
  138,143,142
  139,143,136
  138,143,136
  </code></pre>
  
  <p>This is data from a planar sensor. So Scan_0 is a list or "radial" coordinates for the specific scan at a time stamp. </p>
  
  <p>My plan is to:</p>
  
  <ol>
  <li>Read the CSV file into a list</li>
  <li>Create Separate Array's for each scan (columns)</li>
  <li><p>Turn each element of the scan array into a xyz format like the example below.</p>
  
  <pre><code>scan_0 -----&gt; scan_0
  timestamp_0-&gt; timestamp_0
  7900200-----&gt; 7900200
  logTime_0---&gt; logTime_0
  27:46.8-----&gt; 27:46.8
  distance_0--&gt; distance_0
  132---------&gt; [132*cos(1),132*sin(1),7900200]
  136---------&gt; [136*cos(2),136*sin(2),7900200]
  139---------&gt; [139*cos(3),139*sin(3),7900200]
  138---------&gt;          .          .
  138---------&gt;          .          .
  139---------&gt;          .          .
  138---------&gt; [138*cos(7),139*sin(7),7900200]
  </code></pre></li>
  <li><p>Write the array of xyz coordinates to a new csv file with one coordinate per line'</p></li>
  <li><p>eventually use a trajectory instead of timestamp for the z coordinate from another csv file.</p></li>
  </ol>
  
  <p>I tell you all of this, so you have some context for my motivation. To start this little project, I've decided to simply try and read the csv file into a list and output each of the lines to another csv file... start small right?</p>
  
  <p>here is what I have so far:</p>
  
  <pre><code>import csv 
  
  with open("2016_09_16_14_29_09_953.csv", 'r') as f:
      with open("out.csv", "a") as f1:
          x = csv.reader(f)
          my_list = list(x)
          thedatawriter = csv.writer(f1)
          for row in my_list:
              thedatawriter.write(row)
  </code></pre>
  
  <p>This creates an empty csv file. What am I doing wrong here? I feel like an ant climbing mount Everest. Any help, advice, and guidance is greatly appreciated.  </p>