title: Making regex for preg_match greedy to only accept certain values?
body: <p>I have a CSV file that has a entry of strings that represents time/dates as follows :</p>
  
  <p><code>20190816T16:10:10</code></p>
  
  <p>I have created the following regex to preg_match but want to have the hour/mins and seconds to only allow certain numbers (e.g hours would be 24 hour clock so only accept 00-23, while minutes &amp; seconds would only accept 00-59)</p>
  
  <p><code>/\d{8}[A-Z]\d{2}:\d{2}:\d{2}/</code></p>
  
  <p>Can anyone suggest how to change this to ensure this regex matches the structure I am trying to achieve?</p>