FAQ: Doubly Linked Lists: Python - Adding to the Tail

Frequently Asked Questions Uncategorized
1

Community%20FAQs%20on%20Codecademy%20Exercises
Community%20FAQs%20on%20Codecademy%20Exercises1000×208 141 KB

This community-built FAQ covers the “Adding to the Tail” exercise from the lesson “Doubly Linked Lists: Python”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Pass the Technical Interview with Python

FAQs on the exercise Adding to the Tail

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply (reply) below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

Join the Discussion. Help a fellow learner on their journey.

Ask or answer a question about this exercise by clicking reply (reply) below!
You can also find further discussion and get answers to your questions over in Language Help.

Agree with a comment or answer? Like (like) to up-vote the contribution!

Need broader help or resources? Head to Language Help and Tips and Resources. If you are wanting feedback or inspiration for a project, check out Projects.

Looking for motivation to keep learning? Join our wider discussions in Community

Learn more about how to use this guide.

Found a bug? Report it online, or post in Bug Reporting

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

2

Is there a reason to use if current_head != None for the if statements? Is this just done for clarity for those new to Python? Currently, doing an implicit conversion to bool (if current_head:) is marked as wrong by the exercise.

1 Like
3

Yeah I had the same sort issue than you. I wanted to use if not current_head == None, and I have an error too.
I guess they choose the one most readable…Great to see the way you solved it.

4

I did it this way too!

If current_head is 0 the code block also runs. That checks for if current_head is a falsy value even the ones that are not None so if current_head could be a falsy value and not None and you don’t want the code block to run, then don’t use this form:
if current_head:
.

5

I think that checking the value against None should be changed, even PEP8 recommends using is/is not PEP 8 – Style Guide for Python Code | peps.python.org, yet in the ‘recommended’ solution it’s still equals/not equals sign.