Implementing a Contacts directory in Python

Our task is to implement a smartphone directory that collects contact data from the user until the user prompts the program to. Contact data refers to the contact’s name, phone number, date-of-birth, a category that contact belongs to (Friends, Family, Work, Other), e-mail address. The user may enter as much data as he can in the mentioned data labels. If some labels remain void of data, store it as None. A name & the number is mandatory to create contact. Implement the following operations on the directory: Insert, Delete, Search, Display.

Approach :

We have used 2D list concept and implemented the same in Python3. There are a total of 8 functions used in this code, namely :

  • initial_phonebook() : The first function to run, it initializes the phonebook.
  • menu() : It displays the choices available to the user and returns the choice entered.
  • add_contact() : It adds a new contact to the Contacts directory.
  • remove_existing() : It removes an existing contact from the Contacts directory.
  • delete_all() : It deletes all the contacts from the Contacts directory.
  • display_all() : It displays all the contacts from the Contacts directory.
  • search_existing() : It will search nd display an existing contact in the Contancts directory.
  • thanks() :

Keeping user experience and user interface, we have made the code simple, readable and interactive. You may or may not go for all the features exactly as described below. Please go through the code solution.

Please try to run this code on your Python IDLE as some errors may occur if you run here as user inputs are required. You may also open the IDE page at GFG and run your code there instead of directly running from the code snippet.



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# importing the module
import sys
  
# this function will be the first to run as soon as the main function executes
def initial_phonebook():
    rows, cols = int(input("Please enter initial number of contacts: ")), 5
      
    # We are collecting the initial number of contacts the user wants to have in the
    # phonebook already. User may also enter 0 if he doesn't wish to enter any.
    phone_book = []
    print(phone_book)
    for i in range(rows):
        print("\nEnter contact %d details in the following order (ONLY):" % (i+1))
        print("NOTE: * indicates mandatory fields")
        print("....................................................................")
        temp = []
        for j in range(cols):
                      
        # We have taken the conditions for values of j only for the personalized fields
        # such as name, number, e-mail id, dob, category etc
            if j == 0:
                temp.append(str(input("Enter name*: ")))
                  
                # We need to check if the user has left the name empty as its mentioned that
                # name & number are mandatory fields.
                # So implement a condition to check as below.
                if temp[j] == '' or temp[j] == ' ':
                    sys.exit(
                        "Name is a mandatory field. Process exiting due to blank field...")
                    # This will exit the process if a blank field is encountered.
                      
            if j == 1:
                temp.append(int(input("Enter number*: ")))
                # We do not need to check if user has entered the number because int automatically
                # takes care of it. Int value cannot accept a blank as that counts as a string.
                # So process automatically exits without us using the sys package.
                  
            if j == 2:
                temp.append(str(input("Enter e-mail address: ")))
                # Even if this field is left as blank, None will take the blank's place
                if temp[j] == '' or temp[j] == ' ':
                    temp[j] = None
                      
            if j == 3:
                temp.append(str(input("Enter date of birth(dd/mm/yy): ")))
                # Whatever format the user enters dob in, it won't make a difference to the compiler
                # Only while searching the user will have to enter query exactly the same way as
                # he entered during the input so as to ensure accurate searches
                if temp[j] == '' or temp[j] == ' ':
                                      
                # Even if this field is left as blank, None will take the blank's place
                    temp[j] = None
            if j == 4:
                temp.append(
                    str(input("Enter category(Family/Friends/Work/Others): ")))
                # Even if this field is left as blank, None will take the blank's place
                if temp[j] == "" or temp[j] == ' ':
                    temp[j] = None
                      
        phone_book.append(temp)
        # By this step we are appending a list temp into a list phone_book
        # That means phone_book is a 2-D array and temp is a 1-D array
      
    print(phone_book)
    return phone_book
  
def menu():
    # We created this simple menu function for
    # code reusability & also for an interactive console
    # Menu func will only execute when called
    print("********************************************************************")
    print("\t\t\tSMARTPHONE DIRECTORY", flush=False)
    print("********************************************************************")
    print("\tYou can now perform the following operations on this phonebook\n")
    print("1. Add a new contact")
    print("2. Remove an existing contact")
    print("3. Delete all contacts")
    print("4. Search for a contact")
    print("5. Display all contacts")
    print("6. Exit phonebook")
  
    # Out of the provided 6 choices, user needs to enter any 1 choice among the 6
    # We return the entered choice to the calling function wiz main in our case
    choice = int(input("Please enter your choice: "))
      
    return choice
  
def add_contact(pb):
    # Adding a contact is the easiest because all you need to do is:
    # append another list of details into the already existing list
    dip = []
    for i in range(len(pb[0])):
        if i == 0:
            dip.append(str(input("Enter name: ")))
        if i == 1:
            dip.append(int(input("Enter number: ")))
        if i == 2:
            dip.append(str(input("Enter e-mail address: ")))
        if i == 3:
            dip.append(str(input("Enter date of birth(dd/mm/yy): ")))
        if i == 4:
            dip.append(
                str(input("Enter category(Family/Friends/Work/Others): ")))
    pb.append(dip)
    # And once you modify the list, you return it to the calling function wiz main, here.
    return pb
  
def remove_existing(pb):
    # This function is to remove a contact's details from existing phonebook
    query = str(
        input("Please enter the name of the contact you wish to remove: "))
    # We'll collect name of the contact and search if it exists in our phonebook
      
    temp = 0
    # temp is a checking variable here. We assigned a value 0 to temp.
      
    for i in range(len(pb)):
        if query == pb[i][0]:
            temp += 1
            # Temp will be incremented & it won't be 0 anymore in this function's scope
              
            print(pb.pop(i))
            # The pop function removes entry at index i
              
            print("This query has now been removed")
            # printing a confirmation message after removal.
            # This ensures that removal was successful.
            # After removal we will return the modified phonebook to the calling function
            # which is main in our program
              
            return pb
    if temp == 0:
        # Now if at all any case matches temp shoul've incremented but if otherwise,
        # temp will remain 0 and that means the query does not exist in this phonebook
        print("Sorry, you have entered an invalid query.\
    Please recheck and try again later.")
          
        return pb
  
def delete_all(pb):
    # This function will simply delete all the entries in the phonebook pb
    # It will return an empty phonebook after clearing
    return pb.clear()
  
def search_existing(pb):
    # This function searches for an existing contact and displays the result
    choice = int(input("Enter search criteria\n\n\
    1. Name\n2. Number\n3. Email-id\n4. DOB\n5. Category(Family/Friends/Work/Others)\
    \nPlease enter: "))
    # We're doing so just to ensure that the user experiences a customized search result
      
    temp = []
    check = -1
      
    if choice == 1:
    # This will execute for searches based on contact name
        query = str(
            input("Please enter the name of the contact you wish to search: "))
        for i in range(len(pb)):
            if query == pb[i][0]:
                check = i
                temp.append(pb[i])
                  
    elif choice == 2:
    # This will execute for searches based on contact number
        query = int(
            input("Please enter the number of the contact you wish to search: "))
        for i in range(len(pb)):
            if query == pb[i][1]:
                check = i
                temp.append(pb[i])
                  
    elif choice == 3:
    # This will execute for searches based on contact's e-mail address
        query = str(input("Please enter the e-mail ID\
        of the contact you wish to search: "))
        for i in range(len(pb)):
            if query == pb[i][2]:
                check = i
                temp.append(pb[i])
                  
    elif choice == 4:
    # This will execute for searches based on contact''s date of birth
        query = str(input("Please enter the DOB (in dd/mm/yyyy format ONLY)\
            of the contact you wish to search: "))
        for i in range(len(pb)):
            if query == pb[i][3]:
                check = i
                temp.append(pb[i])
                  
    elif choice == 5:
    # This will execute for searches based on contact category
        query = str(
            input("Please enter the category of the contact you wish to search: "))
        for i in range(len(pb)):
            if query == pb[i][4]:
                check = i
                temp.append(pb[i])
        # All contacts under query category will be shown using this feature
          
    else:
    # If the user enters any other choice then the search will be unsuccessful
        print("Invalid search criteria")
        return -1
    # returning -1 indicates that the search was unsuccessful
      
    # all the searches are stored in temp and all the results will be displayed with
    # the help of display function
      
    if check == -1:
        return -1
        # returning -1 indicates that the query did not exist in the directory
    else:
        display_all(temp)
        return check
        # we're just returning a index value wiz not -1 to calling function just to notify
        # that the search worked successfully
  
# this function displays all content of phonebook pb
def display_all(pb):
    if not pb:
    # if display function is called after deleting all contacts then the len will be 0
    # And then without this condition it will throw an error
        print("List is empty: []")
    else:
        for i in range(len(pb)):
            print(pb[i])
  
def thanks():
# A simple gesture of courtesy towards the user to enhance user experience
    print("********************************************************************")
    print("Thank you for using our Smartphone directory system.")
    print("Please visit again!")
    print("********************************************************************")
    sys.exit("Goodbye, have a nice day ahead!")
  
# Main function code
print("....................................................................")
print("Hello dear user, welcome to our smartphone directory system")
print("You may now proceed to explore this directory")
print("....................................................................")
# This is solely meant for decoration purpose only.
# You're free to modify your interface as per your will to make it look interactive
  
ch = 1
pb = initial_phonebook()
while ch in (1, 2, 3, 4, 5):
    ch = menu()
    if ch == 1:
        pb = add_contact(pb)
    elif ch == 2:
        pb = remove_existing(pb)
    elif ch == 3:
        pb = delete_all(pb)
    elif ch == 4:
        d = search_existing(pb)
        if d == -1:
            print("The contact does not exist. Please try again")
    elif ch == 5:
        display_all(pb)
    else:
        thanks()

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Output : We shall see the output of this program segment by segment.

Initially, the following will be displayed :

…………………………………………………………..
Hello dear user, welcome to our smartphone directory system
You may now proceed to explore this directory
…………………………………………………………..
Please enter initial number of contacts:

In the starting, we shall enter 2 contacts :

Please enter initial number of contacts: 2
[]

Enter contact 1 details in the following order (ONLY):
NOTE: * indicates mandatory fields
…………………………………………………………..
Enter name*: Geeks
Enter number*: 9999999999
Enter e-mail address: gfg@gfg.com
Enter date of birth(dd/mm/yy): 01/01/01
Enter category(Family/Friends/Work/Others): Work

Enter contact 2 details in the following order (ONLY):
NOTE: * indicates mandatory fields
…………………………………………………………..
Enter name*: Sample
Enter number*: 1234567890
Enter e-mail address:
Enter date of birth(dd/mm/yy):
Enter category(Family/Friends/Work/Others):
[[‘Geeks’, 9999999999, ‘gfg@gfg.com’, ’01/01/01′, ‘Work’], [‘Sample’, 1234567890, None, None, None]]
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:



Now to add a new contact, according to the menu we will press 1 :

Please enter your choice: 1
Enter name: Emergency
Enter number: 108
Enter e-mail address:
Enter date of birth(dd/mm/yy):
Enter category(Family/Friends/Work/Others):
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

We can see all the contacts by pressing 5 :

Please enter your choice: 5
[‘Geeks’, 9999999999, ‘gfg@gfg.com’, ’01/01/01′, ‘Work’]
[‘Sample’, 1234567890, None, None, None]
[‘Emergency’, 108, ”, ”, ”]
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

To delete a contact, we have to enter 2 :

Please enter your choice: 2
Please enter the name of the contact you wish to remove: Sample
[‘Sample’, 1234567890, None, None, None]
This query has now been removed
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

To search for a contact, we have to press 4 :



Please enter your choice: 4
Enter search criteria

1. Name
2. Number
3. Email-id
4. DOB
5. Category(Family/Friends/Work/Others)
Please enter: 2
Please enter the number of the contact you wish to search: 9999999999
[‘Geeks’, 9999999999, ‘gfg@gfg.com’, ’01/01/01′, ‘Work’]
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

We can delete all the contacts by pressing 3 :

Please enter your choice: 3
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

To view all the contacts press 5, as we have just deleted them nothing will be displayed :

Please enter your choice: 5
List is empty: []
********************************************************************
SMARTPHONE DIRECTORY
********************************************************************
You can now perform the following operations on this phonebook

1. Add a new contact
2. Remove an existing contact
3. Delete all contacts
4. Search for a contact
5. Display all contacts
6. Exit phonebook
Please enter your choice:

To exit the program, enter 6 :

Please enter your choice: 6
********************************************************************
Thank you for using our Smartphone directory system.
Please visit again!
********************************************************************

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