title: How to extract a substring from a string in PHP until it reaches a certain character?
body: <p>I have part of a PHP application which assess a long string input by the user, and extracts a number which always begins 20 characters into the string the user supplies.</p>
  
  <p>The only problem is that I don't know how long the number for each user will be, all I do know is the end of the number is always followed by a double quote (").</p>
  
  <p>How can I use the PHP substring function to extract a substring starting form a specific point, and ending when it hits a double quote?</p>
  
  <p>Thanks in advance.</p>