如何删除购物车中的数量

Question

如何从购物车中删除数量。 我定义了一个名为 ShoppingCart 的类来表示购物车。

class ShoppingCart:
    # Initialize the shopping cart with an empty list of items
    def __init__(self):
        self.items = []

    # Add an item with a name and quantity to the shopping cart
    def add_item(self, item_name, qty):
        item = (item_name, qty)
        self.items.append(item)

    # Remove an item with a specific name from the shopping cart
    def remove_item(self, item_name):
        for item in self.items:
            if item[0] == item_name:
                self.items.remove(item)
                break

    # Calculate and return the total quantity of items in the shopping cart
    def calculate_total(self):
        total = 0
        for item in self.items:
            total += item[1]
        return total

我正在努力

Cart = shoppingcart()
Cart.remove_item = “orange”

但是我想保留橙色但附加橙色数量

Answer 1

正如其他人评论的那样，不清楚您到底要求什么。以下是从对象调用函数的一个示例：

class ShoppingCart:
    # Initialize the shopping cart with an empty list of items
    def __init__(self):
        self.items = {}

    # Add an item with a name and quantity to the shopping cart
    def add_item(self, item_name, qty):
        self.item = {item_name:qty}
        if item_name in list(self.items.keys()):
            qty_new = self.items[item_name]+qty
            self.items[item_name] = qty_new     
        else:
            self.items[item_name]=qty

    # Remove an item with a specific name from the shopping cart
    def remove_item(self, item_name):
        self.items.pop(item_name, 'Item is not in cart!')
        print(f"all items {item_name} removed from cart")

    # show content of shopping cart
    def show_total(self):
        print("Your cart contain:")
        for item_name, qty in self.items.items():
            print(" ",item_name, qty)
        
# create the object
cart = ShoppingCart()

# add elements 
cart.add_item("Orange",1)
cart.add_item("Orange",1)

# Show content
cart.show_total()

# Reduce amount
cart.add_item("Orange",-1)
cart.show_total()

# Add other items to the cart
cart.add_item("Apple",2)
cart.show_total()

# Remove item
cart.remove_item("Apple")
cart.show_total()

输出：

Your cart contain:
  Orange 2
Your cart contain:
  Orange 1
Your cart contain:
  Orange 1
  Apple 2
Your cart contain:
  Orange 2
  Apple 2
all items Apple removed from cart
Your cart contain:
  Orange 2