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

Computer Science Introduction to Algorithms Algorithms in Code Binary Search in Code

Simohamed ALAOUI
Simohamed ALAOUI
3,580 Points

🤔Im still confused about this part 👉 last = len(list)- 1.

If we deduct 1, we get the 3rd position which is the number 4 (i was thinking why we don't add 1 instead of deducting 1. Please Help!

1 Answer

Steven Parker
Steven Parker
231,268 Points

Since index values begin at 0 instead of 1, the highest possible index (and the index of the last item) is one less than the number of items in the list.