re = /(?<year>\d{4})-(?<month>[01][0-9])-(?<day>[0123][0-9])/m
str = '2018-10-18
2018-1-1
2018-12-31
2018-01-01
'
# 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