re = /^(.*?)(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?(?:,(.+?))?$/mix
str = '1.jpg,2.jpg,3.jpg,4.jpg,5.jpg,6.jpg,7.jpg,8.jpg,9.jpg,10.jpg,11.jpg,12.jpg,13.jpg,14.jpg,15.jpg,16.jpg,17.jpg,18.jpg,19.jpg,20.jpg'
# 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