Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Python Python Basics (2015) Python Data Types Lists

Why shouldn't I use extend to add only one item

In the video he said to use append for adding one item to the list and extend for two or more items only. I tried using extend to add just one number to the list and it worked fine. Is there any particular reason to use append? i'm using python 3.6.4 if it matters.

1 Answer

12,964 Points

Hi William! I just looked at the video transcript and Kenneth doesn't say don't ever use extend for one item. He said:

So the basic rule, if I want to add a single item to a list, I use append.

Whatever that single item is, append puts a single thing onto the end of my_list.

If I want to add multiple items, then I use extend.

Append for one, extend for two or more.

So, you don't have to use extend only for multiple items. But what he's saying is, this is what extend is made to do and this is what append is made to do. :)

Hope this helps, Nakal