🔒 hard time understanding classes

[dim orbit]

I am getting started in my algo and data structs class and I am having a hard time understanding classes as I havent wrote a single line of python in a while. In a provided file my prof creates a class called SLLNode which is just a node for a SLL which contains the data and next node attributes. Then is there is a singlylinkedlist class where there are methods for it and I am writing the code. She created the append portion which is

    def append(self, data: T) -> None:
        if self.head is None:
            self.head = SLLNode(Data)
            self.tail = self.head
            return

        self.tail.next = SLLNode(data)

        self.tail = self.tail.next

and I am having a hard time understanding how self.tail.next works. I kind of understand that self.tail is an instance of SLLNode and SLLNode has an attribute of next but I cant wrap my head around it.

[dawn moss]

@dim orbit

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[neat bolt]

It's just an expression. self is an SLLNode. So is self.tail. So you're just assigning to that .next attribute of self.tail. Draw boxes with arrows, it helps.

Unpack it.

tail_node = self.tail
tail_node.next = SLLNode(data)

Any clearer?

Personally I might write the last 2 lines like this:

end_node = SLLNode(data)
old_tail_node = self.tail
old_tail_node.next = end_node
self.tail = end_node

[cerulean bane]

Draw boxes with arrows, it helps
This sounds so goofy to me, but its very true.
Here is a picture that might visualize a linked list. (just the first result I could find)
img

[neat bolt]

And mapping the above pic to Python, in Python we use None for the null above.

[dawn moss]

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