Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Functional Python The Lambda Lambada Reduce

Posted by John Shockey
John Shockey
45,061 Points

[SOLVED] Completely stuck on task 4 of 4

I'm lost and don't know where to go from here.

prices.py 
from operator import add
from functools import reduce

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

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

total = map(product_sales, prices) + reduce(product_sales, [ ])

1 Answer

Steven Parker
Steven Parker
231,268 Points
Steven Parker
Steven Parker
231,268 Points

You're close...

You figured out the part about using map to generate the totals: map(product_sales, prices) :white_check_mark:

Remember that reduce applies a function to a list, and you're creating the list with map. And you imported the add function already, so you just need to pass the function and the list to reduce:

    total = reduce( add, map(product_sales, prices) )
John Shockey
John Shockey
45,061 Points

Ahhh gotcha. Thanks!