re = /(?=.*\bApple\b)(?=.*\bCar\b)(?=.*\bBat\b)(?!.*(?:,|^)(?:(?!\b(?:Apple|Bat|Car)\b).)+(?:,|$))^.*$/m
str = 'Bat, Car, Apple
Other, Bat, Car, Apple
Car, Bat, Apple
Car, Other, Bat, Apple
Apple, Car, Bat
Apple, Car, Bat, Stick
Bat, Car
Apple
Car, Apple, Bat
Cartography, Apple, Bat, Car'
# Print the match result
str.scan(re) do |match|
puts match.to_s
end
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html