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Python Python Basics Functions and Looping Raise an Exception

Kieran Forbes
Kieran Forbes
3,706 Points
Posted by Kieran Forbes
Kieran Forbes
3,706 Points

My code stops to work when I add the <0 value error

Any help would be appreciated on how I will be able to add a Value Error when the price is less than 0. Thanks!

suggestinator.py 
total = []
prices = []
print("Hi there, and welcome to our store, please enter 5 items you bought today along with their prices")

while len(prices) < 5:
        if prices <=0:
                raise ValueError("This is a negative value")

        try:
                purchase = input("What did you buy today?")
                price = float(input("How much did it cost?"))
                total.append(purchase)
                prices.append(price)
        except ValueError:
                print("Please enter a valid number")



def bubbleSort(nlist):
    sorted = False
    while not sorted:
        swaps = 0
        for i in range(len(nlist) -1):
            if nlist[i] > nlist[i+1]:
                temp1 = nlist[i]
                nlist[i] = nlist[i + 1]
                nlist[i + 1] = temp1
                swaps = swaps + 1
        if swaps == 0:
             sorted = True
    return nlist

bubbleSort(prices)

first_total = (total[0], prices[0])
final_total = list(zip(total, prices))
print(final_total)
discount = first_total
print("Since you bought", len(total), "products with us today, we will now give you the cheapest product for free, meaning you will get", discount, "for free")
totaltotal = prices[1:]
totaltotalt = sum(totaltotal)


print("So the total price that you will pay today is ",totaltotalt)

2 Answers

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,971 Points

You could move it to the try and check the price (not prices)

while len(prices) < 5:
    try:
        purchase = input("What did you buy today?")
        price = float(input("How much did it cost?"))

        if price <=0:
            raise ValueError("This is a negative value")

        total.append(purchase)
        prices.append(price)

    except ValueError:
        print("Please enter a valid number")

Also if you sort prices without making the same changes to total the price no longer corresponds to the correct purchase by index

Kieran Forbes
Kieran Forbes
3,706 Points
Kieran Forbes
Kieran Forbes
3,706 Points

Great solution, thanks

YZ L
YZ L
6,184 Points
YZ L
YZ L
6,184 Points

make a 'for' loop:

for _ in prices:
  if _ <= 0:
    raise ValueError("This is a negative value")
Kieran Forbes
Kieran Forbes
3,706 Points
Kieran Forbes
Kieran Forbes
3,706 Points

Thank you for your reply, can I ask how you would implement that in my code as I am still getting an error?