Deleting a Contact

Part of the Logic & Flow section of Coddy's Lua journey — lesson 46 of 54.

Challenge

Easy

Implement the delete functionality for your contact list application. When the user enters delete, the program should prompt for a name, find that contact in the list, and remove it.

Building on the previous challenge, add functionality to handle the delete command. Loop through the contacts table to find the contact with the matching name, then use table.remove() to delete it from the list. Provide feedback to the user about whether the deletion was successful.

Requirements:

Keep all code from the previous challenge (setup, menu display, main loop, add, list, and search functionality)
When the user enters delete, print: Enter name to delete:
Read the name using io.read()
Use ipairs() to iterate through the contacts table
For each contact, check if the name field matches the name to delete exactly
If a match is found, use table.remove() with the contact's index to delete it
After successful deletion, print: Contact deleted successfully!
If no match is found after checking all contacts, print: Contact not found.
When the list command is used and there are no contacts, print: No contacts available.
The add, list, search, and quit commands should still work as before

Note: The empty list message in this challenge is No contacts available. — make sure to use this exact string, even if a previous lesson used different wording.

Example interaction:

Welcome to Contact List Manager!

Available Commands:
add - Add a new contact
list - Display all contacts
search - Search for a contact
delete - Delete a contact
quit - Exit the program

Enter command:
add
Enter name:
Alice
Enter phone number:
555-1234
Contact added successfully!

Enter command:
add
Enter name:
Bob
Enter phone number:
555-5678
Contact added successfully!

Enter command:
list
Contact List:
1. Alice - 555-1234
2. Bob - 555-5678

Enter command:
delete
Enter name to delete:
Alice
Contact deleted successfully!

Enter command:
list
Contact List:
1. Bob - 555-5678

Enter command:
delete
Enter name to delete:
Charlie
Contact not found.

Enter command:
quit
Goodbye!

Try it yourself

-- Contact List Manager
local contacts = {}

-- Display welcome message
print("Welcome to Contact List Manager!")
print()

-- Display menu
print("Available Commands:")
print("add - Add a new contact")
print("list - Display all contacts")
print("search - Search for a contact")
print("delete - Delete a contact")
print("quit - Exit the program")
print()

-- Main loop
while true do
    print("Enter command:")
    local command = io.read()
    
    if command == "add" then
        print("Enter name:")
        local name = io.read()
        print("Enter phone number:")
        local phone = io.read()
        
        table.insert(contacts, {name = name, phone = phone})
        print("Contact added successfully!")
        print()
        
    elseif command == "list" then
        if #contacts == 0 then
            print("No contacts available.")
        else
            print("Contact List:")
            for i, contact in ipairs(contacts) do
                print(i .. ". " .. contact.name .. " - " .. contact.phone)
            end
        end
        print()
        
    elseif command == "search" then
        print("Enter name to search:")
        local searchName = io.read()
        local found = false
        
        for i, contact in ipairs(contacts) do
            if contact.name == searchName then
                print("Found: " .. contact.name .. " - " .. contact.phone)
                found = true
                break
            end
        end
        
        if not found then
            print("Contact not found.")
        end
        print()
        
    elseif command == "quit" then
        print("Goodbye!")
        break
        
    else
        print("Command not yet implemented")
        print()
    end
end