title: How to get ROS xml param from launch file using Python
body: <p>I have a launch file which extension is xml, and I would like to get the value of a parameter. This launch file is called ardrone.launch</p>
  
  <pre><code>&lt;!-- This is a sample lanuch file, please change it based on your needs --&gt;
  &lt;launch&gt;
      &lt;node name="ardrone_driver" pkg="ardrone_autonomy" type="ardrone_driver" output="screen" clear_params="true"&gt;
          &lt;param name="outdoor" value="1" /&gt;
          &lt;param name="flight_without_shell" value="1" /&gt;
          &lt;param name="max_bitrate" value="4000" /&gt;
          &lt;param name="bitrate" value="4000" /&gt;
          &lt;param name="navdata_demo" value="0" /&gt;
          &lt;param name="altitude_max" value="10000" /&gt;
          &lt;param name="altitude_min" value="50" /&gt;
          &lt;param name="euler_angle_max" value="0.35" /&gt;
          &lt;param name="control_vz_max" value="2000" /&gt;
          &lt;param name="control_yaw" value="1.75" /&gt;
      &lt;/node&gt;
  &lt;/launch&gt;
  </code></pre>
  
  <p>For example, I would like to get the value from altitude_max, altitude_min, and the others using python. I have to add that this file is inside a directory called launch and the file where I am calling it is at a directory called scripts, and scripts and launch are both in the same directory.</p>