title: Retrieve number from the string pattern using regular expression
body: <p>I have a string "Search result:16143 Results found", and I need to retrieve 16143 out of it.</p>
  
  <p>I am coding in ruby and I know this would be clean to get it using RegEx (as oppose to splitting string based on delimiters)</p>
  
  <p>How would I retrieve the number from this string in ruby?</p>