Changing values of a list of namedtuples

Question

I have a list of namedtuples named Books and am trying to increase the price field by 20% which does change the value of Books. I trie

Answer 1

In Python >= 3.7 you can use dataclass decorator with the new variable annotations feature to produce mutable record types:

from dataclasses import dataclass


@dataclass
class Book:
    author: str
    title: str
    genre: str
    year: int
    price: float
    instock: int


BSI = [
    Book("Suzane Collins", "The Hunger Games", "Fiction", 2008, 6.96, 20),
    Book(
        "J.K. Rowling",
        "Harry Potter and the Sorcerer's Stone",
        "Fantasy",
        1997,
        4.78,
        12,
    ),
]

for item in BSI:
    item.price *= 1.10
    print(f"New price for '{item.title}' book is {item.price:,.2f}")

Output:

New price for 'The Hunger Games' book is 7.66
New price for 'Harry Potter and the Sorcerer's Stone' book is 5.26