title: get substring from string based on start and end position python
body: <p>How do I get substring from string based on start and end position and do it for each row in a table. the start and end positions are found in the same table at the same row as an initial string but in a different columns.
  Input:</p>
  
  <pre><code>String                      Start End
  1. Kids walking to school   0     3
  2. Hello world              2     4
  3. Today is a great day     6     9
  </code></pre>
  
  <p>Desired output:</p>
  
  <pre><code>String                      Start End Substring
  1. Kids walking to school   0     3   Kids
  2. Hello world              2     4   llo
  3. Today is a great day     6     9   is a
  </code></pre>