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 Python Collections (2016, retired 2019) Lists Removing items from a list

Using isinstance to check for str and bool. It seems like this should work but I'm not getting past this level.

lists.py
messy_list = ["a", 2, 3, 1, False, [1, 2, 3]]

messy_list.pop(3)
messy_list.insert(0,1)

for n in messy_list:
    if isinstance(n, str):
        messy_list.remove(n)
    elif isinstance(n, bool):
        messy_list.remove(n)

1 Answer

Steven Parker
Steven Parker
230,248 Points

Your idea is good, but there are a couple of implementation issues:

  • altering a list while iterating on it can cause items to be skipped, use a copy for the loop
  • besides str and bool, there's also a list to remove
  • hint: try just removing everything but what you want to keep