# Carly’s Clippers project - module 3 problem with range (step 8)

#1

Hello I struggle to understand why I get different total revenue (1085 instead of 1015) in the range part!

my code:

for i in range(len(hairstyles)):
total_revenue += (prices [i] * last_week[i])
print (total_revenue)

what the video shows:

for i in range(0, len (hairstyles) - 1)):
total_revenue += (prices [i] * last_week[i])
print (total_revenue)

Why is my code wrong? The number of hairstyles is 8, it should cover 0,1,2,3,4,5,6,7 = all 8 elements…I thought he didn’t explain his reasoning for the -1 very well but it appears to work.

Any help is appreciated thanks :).

#2

Hi @khitan,

The video is in error. It should be …

``````for i in range(len(hairstyles)):
``````

In a `range`, the `stop` value is exclusive, meaning it is not included in the result. Since `len(hairstyles)` is `8`, the final value of `i` in the iteration is `7`, which is the index of the last item in each of the lists.

If you subtract `1`, the final items in the lists will be missed.

This output is correct …

``Total Revenue: \$1085.00``

#3

Thanks for the swift reply! Greatly appreciate it!