Delete a line (name, contactnumber, emailaddress) by just searching for name in a phonebook

Question

Good evening, I have a phonebook code but I am missing the delete feature. I cannot seem to make the delete feature work. All other features like insert, view, add contacts are working already.

I created a phnoebook txt file to store any entries.

phonebook = "d://phonebook.txt"
pbfile = open(phonebook, "a+")
pbfile.close


def show_main_menu():
    ''' Show main menu for Phone List '''
    print("\n   *** Phone List Menu ***\n"+
          "------------------------------------------\n"+
          "Enter 1, 2, 3 or 4:\n"+
          "1: Display Your Contacts Records\n" +
          "2: Add a New Contact Record\n"+
          "3: Search your contacts\n"+
          "4: Delete a Contact Record\n"+
          "5: Quit\n**********************")
    choice = input("Enter your choice: ")
    if choice == "1":
        pbfile = open(phonebook, "r+")
        file_contents = pbfile.read()
        if len(file_contents) == 0:
            print("Phone List is empty")
        else:
            print (file_contents)
        pbfile.close
        user_entry = input("Press Enter to Return to Main Menu ...")
        show_main_menu()
    elif choice == "2":
        enter_contact_record()
        user_entry = input("Press Enter to Return to Main Menu ...")
        show_main_menu()
    elif choice == "3":
        search_contact_record()
        user_entry = input("Press Enter to Return to Main Menu ...")
        show_main_menu()
    elif choice == "4":
        delete_contact_record()
        user_entry = ("Please Enter to Return to Main Menu ...")
        show_main_menu()
    elif choice== "5":
        print("Thanks for using Phone List")
    else:
        print("Wrong choice, Please Enter [1 to 5]\n")
        user_entry = input("Press Enter to Return to Main Menu ...")
        show_main_menu()

I added the main menu above to show the menu of the phone book, there should be another choice to delete a contact.

The following code is to search for contact. It will show if a contact is already in the phone book but will mention not on record if there is no contact by the name they searched.

        
def search_contact_record():
    ''' This function is used to searches a specific contact record '''
    contact_search = input("Enter First name to search for contact record: ")

    contact_search = contact_search.title()
    pbfile = open(phonebook, "r+")
    file_contents = pbfile.readlines()
     
    found = False   
    for line in file_contents:
        if contact_search in line:
            print("You searched for:", end=" ")
            print (line)
            found=True
            break
    if  found == False:
        print("There's no contact Record in Phone List with name = " + contact_search )

The next function is to enter contact and add it to the phonebook txt file created in the beginning.

def enter_contact_record():
    ''' It  collects contact info firstname, last name, email and phone '''
   
    first = input('Enter First Name: ')
    first = first.title()
    last = input('Enter Last Name: ')
    last = last.title()
    phone = input('Enter Phone number: ')
    email = input('Enter E-mail: ')
    contact = ("[" + first + " " + last + ", " + phone + ", " + email +  "]\n")
    pbfile = open(phonebook, "a")
    pbfile.write(contact)
    print( "This contact\n " + contact + "has been added successfully!")

#def delete_contact():
    

show_main_menu()

I got confused on the part how to delete the contact from the txt phonebook. Last delete lines I have trying was the following

def delete_contact_record():
            #Initiate a name variable
    contact_delete = input('Enter the name of the contact you wish to delete: ').title()
    
    pbfile = open(phonebook, "r+")
    file_contents = pbfile.readlines()
    
    found = False   
    for line in file_contents:
        if contact_delete in line:
            confirm = input('Are you sure you wish to delete '+contact_delete+' y/n?: ')
            print(confirm)
            
            if confirm == 'y':
                del phonebook[contact_delete]
            found = True
            
    if found == False:
        print('That contact does not exist! Return to the main menu to enter the contact')

it works up to the line asking for confirmation y/n. But when I enter Y, I get a TypeError: 'str' object does not support item deletion

Thank you.

Answer 1

Your main problem is that your phone book is a flat file. As such, a deletion is "rewrite the entire file, but without the deleted record."

This is, needless to say, very inefficient.

You will also have problems in the future with spurious matches for searches, since contact_search in line is perfectly happy to match parts of names.

Personally, I'd recommend using an SQLite3 database instead of a flat file (SQLite3 support is built in to Python). SQLite3 databases are actually single files, but you can use almost all of the SQL language to perform structured queries, and let it manage the file for you.

If writing SQL is too daunting, the SQLAlchemy Python package can help by making database tables work like Python classes.