re = /(?=\b.{12}\b)(?=\b[a-z0-9]*[A-Z][a-z0-9]*\b)(?=\b[a-zA-Z]*[0-9][a-zA-Z]*\b)\b\w{12}\b/m
str = 'Generalken0b Generalken0bi generalken0b
General
ken0b
Generalk3n0b
Generalkenob
G3neralkenob
ggggggggggg0 ggggggggggG0 GeneralKen0b
A5abcdefghij - match
dasdaA4avxsa - match
AA5sssaaaaaa - no match
A55asdasdasa - no match
ab5DaeFsasfg - no match'
# 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