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Start your free trialJoost Pijnaker
623 PointsCheck tickets for number input
Hi,
When checking for number input it directs to a ValueError while the input should be an integer.
TICKET_PRICE = 10
tickets_remaining = 100
while tickets_remaining >= 1:
print("There are {} tickets available.".format(tickets_remaining))
name = input("What is you're name? ")
tickets = input("How many tickets would you like {}? ".format(name))
try:
tickets = int(tickets)
if tickets <= tickets_remaining:
raise ValueError("There are only {} tickets remaining.".format(tickets_remaining))
except ValueError as err:
print("Put in only numbers! {}. Try again".format(err))
else:
price = tickets * TICKET_PRICE
print("The price for {} tickets is {} dollars.".format(tickets, price))
answer = input("Do you want to proceed with buying {} tickets? Y/N ".format(tickets))
if answer.lower() == "y":
print("SOLD!")
tickets_remaining -= tickets
else:
print("Thanks for visiting {}!".format(name))
print("We are sold out!")
When I put in a number it returns: "Put in only numbers!"
2 Answers
Steven Parker
231,172 PointsIf a non-integer was input, the video code would respond to a ValueError raised by the system when the conversion failed. It would print out something like: "Oh, no, we ran into an issue! Invalid literal for int() with base 10".
Give it a try and see!
Joost Pijnaker
623 PointsExactly my point. You would want a user-friendly output here like there was in the exercise before.
Steven Parker
231,172 PointsAs you say, creating custom messages had already been demonstrated in another exercise. But it would be simple enough to replace the standard message with a custom one here:
except ValueError as err:
if ("invalid literal" in str(err)):
# use custom message for bad characters
print("You must enter a number, not letters, here!")
else:
# include the error text in the output
print("Oh no, we ran into an issue. {} Please try again.".format(err))
Joost Pijnaker
623 PointsVery helpful! This clears a lot. So you take the output of the error and customise based on that.
Joost Pijnaker
623 PointsJoost Pijnaker
623 PointsOkay found the solution: tickets should be > in stead of <=
if tickets > tickets_remaining:
Second thing it should raise a general exception in stead of checking for numbers, but this is actually bad habit if you ask me. How would Graig's final code respond to a non-integer value for tickets?