re = /^(?!.*([A-Z0-9])\1{3})[A-Z0-9]+$/m
str = '1AAA23
2AAAA34
22A22B5
A222256
VN00000
111123
1111AA
111AAA
1A'
# 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