Question

Make a Backwards Phonebook from a Regular Phonebook

Answer 1

Answer:

Code in Python is given. Take note of the instruction in bold font

Explanation:

You will need to update the below two lines in your system based on the file path -

backward_phone_number('F:\\phone_number_input.txt','F:\\phone_number_output.txt')

def backward_phone_number(input_file,output_file):

   ph_num_dictionary={}

   entries=[]

   #########################################################

   with open(input_file,'r') as read_file:

       entries=read_file.readlines()[1:]

   for entry in entries:

       ph_num_name=entry.split()

       ph_number=ph_num_name[1].strip()

       name=ph_num_name[0].strip()

       if ph_num_dictionary.get(ph_number)==None:

           name_list=[name]

           ph_num_dictionary[ph_number]=name_list

       else:

           ph_num_dictionary.get(ph_number).append(name)

   #########################################################

   ph_num_dictionary = dict(sorted(ph_num_dictionary.items(),key=lambda pair:pair[0]))

   with open(output_file,'w+') as write_file:

       write_file.write('Telephone Number\tName\r\n')

       for num,name in ph_num_dictionary.items():

           if len(name)==1:

               write_file.write(num+'\t'+name[0]+'\r\n')

           else:

               name.sort()

               for person in name:

                   write_file.write(num + '\t' + person + '\r\n')

backward_phone_number('F:\\phone_number_input.txt','F:\\phone_number_output.txt')