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 Collections (2016, retired 2019) Lists Growing Lists

Mirza Gogic
Mirza Gogic
4,342 Points
Posted by Mirza Gogic
Mirza Gogic
4,342 Points

Why is + ["list item"] different than += ["list item"]

Why is + ["list item"] different than += ["list item"].

Why is += ["list item"] permanent? and just + ["list item"] is not?

1 Answer

matth89
matth89
17,826 Points
matth89
matth89
17,826 Points

By using the += compound operator, you are assigning the result of the operation to the variable. If you were to just use the + operator, you would get the result of that operation, but it wouldn't be saved into that variable. an example in the shell:

>>> a = 10
>>> a + 5
15
>>> a
10
>>> a += 5
>>> a
15