title: How to split a dataframe by week on a particular starting weekday (e.g, Thursday)?
body: <p>I'm using Python, and I have a Dataframe in which all dates and weekdays are mentioned.
  And I want to divide them into Week (Like - Thursday to Thursday)</p>
  <p>Dataframe -
  <a href="https://i.stack.imgur.com/ziJZy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ziJZy.png" alt="enter image description here" /></a></p>
  <p>And Now I want to divide this dataframe in this format-</p>
  <pre><code>Date    Weekday
  0   2021-01-07   Thursday
  1   2021-01-08     Friday
  2   2021-01-09   Saturday
  3   2021-01-10     Sunday
  4   2021-01-11     Monday
  5   2021-01-12    Tuesday
  6   2021-01-13  Wednesday
  7   2021-01-14   Thursday,
  
  Date    Weekday
  0   2021-01-14   Thursday
  1   2021-01-15     Friday
  2   2021-01-16   Saturday
  3  2021-01-17     Sunday
  4  2021-01-18     Monday
  5  2021-01-19    Tuesday
  6  2021-01-20  Wednesday
  7  2021-01-21   Thursday,
  
  Date    Weekday
  0  2021-01-21   Thursday
  1  2021-01-22     Friday
  2  2021-01-23   Saturday
  3  2021-01-24     Sunday
  4  2021-01-25     Monday
  5  2021-01-26    Tuesday
  6  2021-01-27  Wednesday
  7  2021-01-28   Thursday,
  Date    Weekday
  0  2021-01-28   Thursday
  1  2021-01-29     Friday
  2  2021-01-30   Saturday.
  </code></pre>
  <p>In this Format but i don't know how can i divide this dataframe.</p>