title: What PHP function to parse this timestamp 42866.32972
body: <p>I am looking for the correct PHP function to parse this timestamp.</p>
  
  <p>I have a range of timestamps that I need to parse in PHP however I can't find the correct function to use. The timestamps are in the format "42866.32972".</p>
  
  <p>Excel converts "42866.32972" to "2017-05-11 07:54:48" using the format "YYYY-MM-DD hh:mm:ss" however I can't find the function to parse this timestamp format in PHP.</p>
  
  <p>I have tried to parse this with DateTime and Date to no avail.</p>
  
  <p>What is the timestamp format and how can I parse this?</p>