Python - Build a basic To-Do List Project: Solutions and Explanations
To-Do List Application:
Build a basic to-do list application where users can add, edit, and delete tasks.
Input values:
User interacts with the application through commands to add, edit, or delete tasks.
Output value:
Updated the to-do list based on user actions.
Example:
Input values: 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 1 Enter task: Buy groceries Output value: Task added successfully.
Input values: 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 2 Enter task index to edit: 1 Enter new task: Buy weekly groceries Output value: Task edited successfully.
Input values: 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 3 Enter task index to delete: 1 Output value: Task deleted successfully.
Input values: 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 4
Here are two different solutions for a basic to-do list application in Python. This application will allow users to add, edit, and delete tasks using a command-line interface.
Solution 1: Basic Approach Using a While Loop and List Operations
Code:
# Solution 1: Basic Approach Using a While Loop and List Operations
# Initialize an empty list to store tasks
tasks = []
# Function to display the available options
def display_menu():
print("\n1. Add Task")
print("2. Edit Task")
print("3. Delete Task")
print("4. Exit")
# Start an infinite loop to continuously interact with the user
while True:
# Display the menu options
display_menu()
# Get the user's choice
choice = input("Select an option: ")
# Option 1: Add Task
if choice == '1':
# Prompt the user to enter a task
task = input("Enter task: ")
# Add the task to the list
tasks.append(task)
print("Task added successfully.")
# Option 2: Edit Task
elif choice == '2':
# Check if there are tasks available to edit
if tasks:
# Display the current tasks with their indices
for index, task in enumerate(tasks):
print(f"{index + 1}. {task}")
# Prompt the user to enter the index of the task to edit
try:
task_index = int(input("Enter task index to edit: ")) - 1
# Check if the entered index is valid
if 0 <= task_index < len(tasks):
# Prompt the user to enter a new task
new_task = input("Enter new task: ")
# Update the task at the specified index
tasks[task_index] = new_task
print("Task edited successfully.")
else:
print("Invalid index.")
except ValueError:
print("Please enter a valid number.")
else:
print("No tasks available to edit.")
# Option 3: Delete Task
elif choice == '3':
# Check if there are tasks available to delete
if tasks:
# Display the current tasks with their indices
for index, task in enumerate(tasks):
print(f"{index + 1}. {task}")
# Prompt the user to enter the index of the task to delete
try:
task_index = int(input("Enter task index to delete: ")) - 1
# Check if the entered index is valid
if 0 <= task_index < len(tasks):
# Remove the task at the specified index
tasks.pop(task_index)
print("Task deleted successfully.")
else:
print("Invalid index.")
except ValueError:
print("Please enter a valid number.")
else:
print("No tasks available to delete.")
# Option 4: Exit
elif choice == '4':
# Exit the application
print("Exiting the application. Goodbye!")
break
# Handle invalid menu choices
else:
print("Invalid choice. Please select a valid option.")
Output:
1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 1 Enter task: Buy daily groceries Task added successfully. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 2 1. Buy daily groceries Enter task index to edit: 1 Enter new task: Buy weekly groceries Task edited successfully. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 3 1. Buy weekly groceries Enter task index to delete: 1 Task deleted successfully. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 4 Exiting the application. Goodbye!
Explanation:
- Uses a simple list ('tasks') to store tasks and a 'while' loop to provide a continuous menu-driven interface.
- Contains menu options for adding, editing, and deleting tasks.
- Utilizes basic list operations ('append', 'pop', and direct indexing) to manage tasks.
- Handles user input and errors with simple conditionals.
- This approach is straightforward but less organized as the code grows.
Solution 2: Using a Class to Encapsulate the To-Do List Functionality
Code:
# Solution 2: Using a Class to Encapsulate the To-Do List Functionality
class ToDoList:
"""Class to handle to-do list operations"""
def __init__(self):
# Initialize an empty list to store tasks
self.tasks = []
def display_menu(self):
"""Display menu options to the user"""
print("\n1. Add Task")
print("2. Edit Task")
print("3. Delete Task")
print("4. Exit")
def add_task(self):
"""Add a new task to the list"""
task = input("Enter task: ")
self.tasks.append(task)
print("Task added successfully.")
def edit_task(self):
"""Edit an existing task"""
if self.tasks:
self.display_tasks()
try:
task_index = int(input("Enter task index to edit: ")) - 1
if 0 <= task_index < len(self.tasks):
new_task = input("Enter new task: ")
self.tasks[task_index] = new_task
print("Task edited successfully.")
else:
print("Invalid index.")
except ValueError:
print("Please enter a valid number.")
else:
print("No tasks available to edit.")
def delete_task(self):
"""Delete a task from the list"""
if self.tasks:
self.display_tasks()
try:
task_index = int(input("Enter task index to delete: ")) - 1
if 0 <= task_index < len(self.tasks):
self.tasks.pop(task_index)
print("Task deleted successfully.")
else:
print("Invalid index.")
except ValueError:
print("Please enter a valid number.")
else:
print("No tasks available to delete.")
def display_tasks(self):
"""Display all tasks with their indices"""
for index, task in enumerate(self.tasks):
print(f"{index + 1}. {task}")
def run(self):
"""Run the to-do list application"""
while True:
self.display_menu()
choice = input("Select an option: ")
if choice == '1':
self.add_task()
elif choice == '2':
self.edit_task()
elif choice == '3':
self.delete_task()
elif choice == '4':
print("Exiting the application. Goodbye!")
break
else:
print("Invalid choice. Please select a valid option.")
# Create an instance of the ToDoList class and run the application
todo_list = ToDoList()
todo_list.run()
Output:
1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 1 Enter task: Buy daily groceries Task added successfully. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 2 1. Buy daily groceries Enter task index to edit: Buy weekly groceries Please enter a valid number. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 3 1. Buy daily groceries Enter task index to delete: 1 Task deleted successfully. 1. Add Task 2. Edit Task 3. Delete Task 4. Exit Select an option: 4 Exiting the application. Goodbye!
Explanation:
- Uses a 'ToDoList' class to encapsulate all functionality related to the to-do list, making the code modular and easy to maintain.
- The class has methods for adding ('add_task'), editing ('edit_task'), deleting ('delete_task'), and displaying tasks ('display_tasks').
- The 'run' method manages the application's main loop, calling other methods as needed.
- This approach is more organized and makes the code easier to extend and maintain by leveraging Object-Oriented Programming (OOP) principles.
Note:Both solutions achieve the required functionality for a to-do list application, but Solution 2 provides a more modular, organized, and scalable structure by using OOP principles.
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