re = /^5[1-5]\d{14}$/m
str = '5245123412347894
5645123412347894
5241123412347894
6245123412347894
12451234123478AA'
# 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