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

reduce , map and add error

Finally, we're ready to find our totals. Create a variable named total. Use map() to find the per-product totals for each item in prices, then use reduce (and add) to find the total value.

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(item):
  return item[0] * item[1]


total = reduce(add , map(product_sales,prices))

1 Answer

Steven Parker
Steven Parker
228,978 Points

I'm not sure why, but that space between add and the comma seems to upset the challenge checker.

:point_right: Just remove that space.

You also have a stray call to add on the line above (but the checker seems to ignore that).

:information_source: You might want to report this funny space issue to Treehouse Support. It may get you an Exterminator badge.

Kenneth Love
Kenneth Love
Treehouse Guest Teacher

Yep, I was being too picky.

It's best to avoid spaces like that, but they shouldn't make you fail.