This community-built FAQ covers the “Linked List Implementation I” exercise from the lesson “Linked Lists: Python”.

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## FAQs on the exercise Linked List Implementation I

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Hello,

Can somebody please explain the logic of the solution for step 1?
def init(self, value=None):

Why is it correct like this if head_node is not an argument of init()? Moreover, why is self.value = value mentioned?

My code was:
self.value = value

It didn’t work because I put head_node as an argument for init(). I would appreciate a clear answer so many thanks in advance!

3 Likes

i am facing the same question bro … have you figured it out?

``````self.head_node = Node(value)
``````

what is the meaning of this line?

1 Like

I am confused by this line of code as well…

As we all read before coming to this lesson, linked lists are composed of nodes. The line you guys mention `self.head_node = Node(value)` means that our LinkedList instance is also the head node of a linked list.

Let’s say we create an instance of the LinkedList class:

`hello = LinkedList(5)`

our new LinkedList instance object `hello` will have a self.value of 5, and will also be a head_node, which will be Node(5). Remember w/e you put into the `__init__` method will happen when you create an object.

You can test putting these lines at the end of your code:

``````hello = LinkedList(5)
print(hello.value)
``````

first and second print should return 5; the third one will tell you that it’s a .Node object. In few words: hello is LinkedList(5) and also a head_node whose value is 5, or Node(5)

2 Likes

Also came here seeking the answer to this question.

You set the self.head_node = Node(value), to be able to reach the methods of the Node class by using self.head_node

2 Likes

It means that, within the class LinkedList, we are setting the instance attribute (which we call head_node) equal to an instance of the class Node with data equal to “value”.

This question is for the page right after because I could not find the exact forum page for it (https://www.codecademy.com/courses/linear-data-structures/lessons/learn-linked-lists-python/exercises/linked-lists-python-list-ii)

Why does this while loop construction not work as intended?

``````def stringify_list(self):
value_holder = ''