re = /(?<=\s)\d(?:(?:-())?\d){5}(?=\s)\1/
str = 'то есть, матчится:
111-111
11-1111
1-111-11
не матчится:
111111
-111111
111111-
111--111
11-11
1111-1111
'
# 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