title: Python programming without loops
body: <p>I have a list of clients who usually call (like in a support call center) asking about different topics.
  I want to know if these clients, grouped per client (ins_no), have called in the last 30 days about the same topics.
  I working with a 10 million records dataset and I need to do this without loops.</p>
  <p>Can anyone help please?</p>
  <p>This is an example of what I have</p>
  <p><a href="https://i.stack.imgur.com/zv2s6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zv2s6.png" alt="enter image description here" /></a></p>
  <p>And what I need</p>
  <p><a href="https://i.stack.imgur.com/UDewG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UDewG.png" alt="enter image description here" /></a></p>
  <p>I use CSV text file and I use python with its libraries (pandas,numpy...)
  Thank you</p>