Recording chosen books

books_receipt.py

import sqlite3
db = sqlite3.connect('bookshop.db')
result = db.cursor().execute("SELECT * FROM books").fetchall()
db.close()

my_books = []

menu = """Bookshop menu.
1: Choose book
2: View my books
3: Exit
>> """

menu_choice = int(input(menu))
while menu_choice != 3:
    if menu_choice == 1:
        n = len(result)
        i = 0
        while i < n:
            print(i, result[i][1]) #e.g.: 10 The Gruffalo
            i = i + 1
        choice = int(input("Enter book num >> "))
        my_books.append(result[choice])
        
    if menu_choice == 2:
        print(my_books)
        
    menu_choice = int(input(menu))
How this works:

    Core Activities:

  1. Run the code above and purchase some books.
  2. Explain in your own words how this line of code works: my_books.append(result[choice])

    3. Extension Activities:

  3. When i chose to view the books I have chosen (currently choice number 2 in this program), make this program only show the titles of the books I have chosen. Hint: You will need another loop, and this: n = len(my_books)
  4. When i exit the program, print out the my_books list in a presentable format, that shoes me all the titles, authors and prices, total price, total credit and credit remaining. It might look like this: 
    Where's Wally by Martin Hanford. Price: $20.8
The Gruffalo by Donaldson, Julia. Price: $21.95
Total price: $42.75
Total credit: $50
Credit remaining: $7.25
  5. Could the n = len(result) variable (that stores the number of tuples in the books dataset) be calculated at launch of this program (i.e. when i first run the SQL query)? Is there any need for this variable to be recalculated every time I choose choice number 1? Test and discuss.