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Python Functional Python The Lambda Lambada Reduce

Passing tuple as argument

For the following question, why doesn't the code below work?

We have a bunch of prices and sales numbers and we need to find out our total earnings. 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.

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

def product_sales((price, unit)):
    return price * unit

1 Answer

Steven Parker
Steven Parker
229,582 Points

Python may not be as smart as you think.

It's a clever idea, but I don't think Python supports destructuring in parameters. Instead, try using a single variable name to represent the passed tuple. Then, in the function you can use subscripting (using the "[]" operator) to select specific elements of the tuple. Or you can just unpack the tuple on a separate line:

    price, unit = passed_tuple