re = /^\d{1,3}(,\d{3})*$/m
str = '42
1,234
6,368,745
6,368,745,123
12,34,567
123233
999999999,999
'
# 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