Sum 未在 python 中指定的列表上执行加法

Question

So i've got the list, i've changed it from strings to integers and now i need to add them all up for a total. The only thing is, my code is not doing the calculation, even when the function is called. Here's my code;

    # create an empty list for your products.
products = []

# Asking for the number of elements to be inputted.
n = int(input("Enter number of products you're buying : "))

# Some UI for the customer.
print("What are these products?")
# iterating until the range that has been chosen.
for i in range(0, n):
    ele = input()

    products.append(" - " + ele)  # adding the element


def totalPrice():
    price = [int(cost[i])]
    print(sum(price))


# Some UI for the customer.
print("How much do those items cost?")
# create an empty list for your prices.
cost = []

# iterating until the range of the products array.
for i in range(products.__len__()):
    ele = str(input())

    cost.append(ele)  # adding the element

# concatenating the lists, putting them in descending order and displaying them.
newList = [i + j for i, j in zip(cost, products)]
newList.sort(reverse=True)
print("Your products are : " + str(newList))


totalPrice()

The function should change the 'cost' list of strings to integers in a new list and add them all together, if i try to target the index of the 'price' list, it gives mean an iteration error. Do i need to specify addition? Am i using the wrong function?

Answer 1

In the function,

price = [int(cost[i])]

This puts a single element into the list price , using the global value of i that was left over after that for i in range(products.__len__()): loop ran at the top level. (Incidentally, don't call .__len__() yourself - the built-in len is designed to do it for you - and don't loop that way anyway .)

if i try to target the index of the 'price' list, it gives mean an iteration error.

I have no idea what this is supposed to mean.

If you want to build a list of values corresponding to the original list, then you need to actually do that - either by iterating with a for loop, or using a comprehension:

price = [int(c) for c in cost]