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Python Functional Python The Lambda Lambada Reduce

Calvin Hoag
Calvin Hoag
8,515 Points

Unhelpful error feedback

Challenge Task 1 of 4 says "Let's start by writing a function named product_sales that takes a single two-member tuple made up of a price and a number of units sold. product_sales should return the product of the price and the number of units." - I don't know if I have the answer or not but neither the video, or the error feedback is being helpful. I don't understand where the error "Bummer! product_sales threw an exception when given the argument (10.5, 2)"

prices = [
    (6.99, 5),
    (2.94, 15),
    (156.99, 2),
    (99.99, 4),
    (1.82, 102)

def product_sales(x, y):
    return x * y

1 Answer

Steven Parker
Steven Parker
229,017 Points

Those "bummer" messages aren't always helpful.

:point_right: So here's some hints:

  • the challenge says the function should take a single argument (yours currently takes two).
  • the argument will be a two-member tuple, so you will subscript it to get the 2 values
  • subscripting is done with brackets ("[]")
  • the indexes of tuple members starts with 0
Calvin Hoag
Calvin Hoag
8,515 Points

Thank you!

def product_sales(x):
    return x[0] * x[1]

Where does it get the argument (10.5, 2)? Is that a built in test happening behind the scenes?