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 Introducing Lists Using Lists Mutability

Blair Walker
Blair Walker
12,672 Points

Doesn't the last example at the end of the video show that this actual "inventory" list is empty?

I tried to call back the list, but nothing is in there. And in the video, he calls "inventory" and its empty. Is this how it should be? Where did the list go?

1 Answer

Travis Alstrand
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Travis Alstrand
Data Analysis Techdegree Graduate 47,479 Points

Yes, he states at about 8:18 that he's looping over a copy but removing from the actual list. He's doing this because when looping over the actual list and trying to remove them, he hit the issues shown where two items still remained. So by looping over a copy, he's still able to access the same item variable, but he removes it from the actual list instead.

I hope that makes sense :smile:

You can read more on Shallow copies (what was seen here) and deep copies here