A dictionary provides a convenient way to map one set of values to another. For example, this dictionary maps doctor names to their corresponding ID codes:

doctortable = {
   'Smith':  '123',
   'Doe':    '908',
   'Jones':  '087',
   'Thomas': '416',
   'Adams':  '850',
}

To access this table, you can use the following code:

if doctor in doctortable:
	doctorid = doctortable[doctor]
else:
	# use '000' to indicate an unknown doctor
	doctorid = '000'

If you need to add another doctor to this table, all you need to do is add another key-value pair to the dictionary.