Python shopping cart add to cart, get total get num items

问题

I am studying for my final and this was a quiz question I missed. I need most of the help on the getTotal method. I need to loop through the list, find the price of each item, add the price to the total and return the total. I struggle with loops and I am not sure how to pull the second item out of a list.. [1] ?? I have tried many ways and am getting frustrated.

If there is anyone up that is willing to help me that would be great. I am still learning and am new at this so go easy on me, but I really want to learn it. It's probably not as hard as I make it out to be, but Ill be waiting for some input. Thank you!

class Item: 
    def __init__(self, name, price):
        self.name = name
        self.price = price

    def getPrice(self):
        return self.price

    def getName(self):
        return self.name

class Cart:
    def __init__(self, list):
        self.list = []

    def addItem(self, item):
        self.list.append(self.list)

    def getTotal(self):
        total = 0
        for item in self.list:
            name, price = item # or price = item[1]
            total = total + price

    def getNumItems(self):
        count = 0
        for c in range(self.list):
            count = self.list + 1
            return count

    def removeItem(self, item)
        #removes the item from the cart's item list

def main():
    item1 = Item("Banana", .69)
    item2 = Item("Eggs", 2.39)
    item3 = Item("Donut", .99)
    c = Cart()
    c.addItem(item1)
    c.addItem(item2)
    c.addItem(item3)
    print "You have %i items in your cart for a total of $%.02f" %(c.getNumItems(), c.getTotal())
    c.removeItem(item3)
    print "You have %i items in your cart for a total of $%.02f" % (c.getNumItems(), c.getTotal())
main()  

回答1:

Here gives the time and I changed the code and now it is fully functional shopping cart

class Item(object): 
    def __init__(self, unq_id, name, price, qty):
        self.unq_id = unq_id
        self.product_name = name
        self.price = price
        self.qty = qty


class Cart(object):
    def __init__(self):
        self.content = dict()

    def update(self, item):
        if item.unq_id not in self.content:
            self.content.update({item.unq_id: item})
            return
        for k, v in self.content.get(item.unq_id).iteritems():
            if k == 'unq_id':
                continue
            elif k == 'qty':
                total_qty = v.qty + item.qty
                if total_qty:
                    v.qty = total_qty
                    continue
                self.remove_item(k)
            else:
                v[k] = item[k]

    def get_total(self):
        return sum([v.price * v.qty for _, v in self.content.iteritems()])

    def get_num_items(self):
        return sum([v.qty for _, v in self.content.iteritems()])

    def remove_item(self, key):
        self.content.pop(key)


if __name__ == '__main__':
    item1 = Item(1, "Banana", 1., 1)
    item2 = Item(2, "Eggs", 1., 2)
    item3 = Item(3, "Donut", 1., 5)
    cart = Cart()
    cart.update(item1)
    cart.update(item2)
    cart.update(item3)
    print "You have %i items in your cart for a total of $%.02f" % (cart.get_num_items(), cart.get_total())
    cart.remove_item(1)
    print "You have %i items in your cart for a total of $%.02f" % (cart.get_num_items(), cart.get_total())

And a output is:

You have 8 items in your cart for a total of $8.00
You have 7 items in your cart for a total of $7.00

回答2:

for getTotal:

def getTotal(self):
    total = 0
    for item in self.list:
        name, price = item # or price = item[1]
        total = total + price

BTW, Your addItem and getNumItems method are also wrong. Since it is final, you should try to understand what you are working on.

来源：https://stackoverflow.com/questions/13873523/python-shopping-cart-add-to-cart-get-total-get-num-items