# Ruby program of sub and gsub method in a string
  
roll = "2004-959-559 # This is Roll Number"
  
# Delete Ruby-style comments
roll = roll.sub!(/#.*$/, "")   
puts "Roll Num : #{roll}"
  
# Remove anything other than digits
roll = roll.gsub!(/\D/, "")    
puts "Roll Num : #{roll}"

Roll Num : 2004-959-559 
Roll Num : 2004959559

# Ruby program of sub and gsub method
text = "geeks for geeks, is a computer science portal"
  
# Change "rails" to "Rails" throughout
text.gsub!("geeks", "Geeks")
  
# Capitalize the word "Rails" throughout
text.gsub!(/\bgeeks\b/, "Geeks")
puts "#{text}"

Geeks for Geeks, is a computer science portal