title: Converting string to any type to do math operations
body: <p>df = </p>
  
  <pre><code>  lat/long0         lat/long1       lat/long2       lat/long3   
  1 45.1024 7.7498    45.1027 7.75    45.1072 7.7568  45.1076 7.7563
  2 45.0595 7.6829    45.0595 7.6829  45.0564 7.682   45.0533 7.6796
  </code></pre>
  
  <p>My DataFrame is str(string) type. Merged latitude and longitude with 'space'. And when I want to do some math operations I get the Value Error: could not convert string to float.</p>
  
  <p>Namely, I want to take difference between rows by taking into account the order of latitude and longitude:</p>
  
  <pre><code>lat/long0  
  45.1024-45.0595 7.7498-7.6829
  </code></pre>
  
  <p>Actually I will calculate distances (ex. euclidean, manhattan distance and etc.) and main problem is to change the type to type able to do math</p>