My solutions for DBC prep exercise using regular expressions

ssn_regexp.rb

# Determine whether a string contains a Social Security number.
def has_ssn?(string)
  %r{\d{3}\-\d{2}-\d{4}} =~ string 
end
 
# Return the Social Security number from a string.
def grab_ssn(string)
  string.slice(/\d{3}\-\d{2}\-\d{4}/)
end
 
# Return all of the Social Security numbers from a string.
def grab_all_ssns(string)
  string.scan(/\d{3}\-\d{2}\-\d{4}/)
end
 
# Obfuscate all of the Social Security numbers in a string. Example: XXX-XX-4430.
# use sub or gsub -- gsub changes all of the occurrences
def hide_all_ssns(string)
  string.gsub(/\d{3}\-\d{2}\-/, "XXX-XX-")         
end
 
# Ensure all of the Social Security numbers use dashes for delimiters.
# Example: 480.01.4430 and 480014430 would both be 480-01-4430.
def format_ssns(string)
  if string.match(/\b\d{9}\b/)
    string.insert(5, '-')  # start inserting from the rightmost side
    string.insert(3, '-')
	  string.gsub(/\b\D\b/) { |m| '-' }
	else
	  return string 
	end
end
 
puts has_ssn?("444-33-4327")
puts grab_ssn("please confirm your identity: 542-54-1422")
puts grab_all_ssns("554-43-9871 : 212-54-1422")
puts hide_all_ssns("554-43-9871 : 212-54-1422")
puts format_ssns("234601422, 350.80.0744, 013-60-8762")