re = /^1?[-. ]*([0-9]{3}){1}[-. ]*([0-9]{3}){1}?[-. ]*([0-9]{4}){1}$/m
str = '1 555 555 5555'
# 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