This is a singly linked list implemented in a Python class LinkedList.
Nodes are added by the LinkedList class's insert method.
The python magic methods __iter__, __getitem__, __delitem__, and __len__ are also implemented for convenience.
This implementation stores nodes in either ascending (the default) or descending order according the the node's value attribute.
To reverse the order of nodes use the instance method reverse to reverse the list in place.
>>> from linked_list import LinkedList
>>>
>>> ll = LinkedList()
>>>
>>> ll.insert(3)
>>> ll.head.value
3
>>>
>>> ll.insert(1)
>>> ll.head.value # 1 is placed before 3 even though it was added afterwards
1
>>>
>>> ll.insert(5)
>>> ll.insert(9)
>>> for node in ll: # Iteration works as expected
... print(node.value)
...
1
3
5
9
>>> len(ll) # The length of the list can be found in the usual way
4
>>>
>>> ll[1].value # Nodes can be accessed like in a normal Python list
1
>>> del ll[1] # Node deletion also works like in a normal list
>>> ll[1]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "D:\Courses\python-oop\linked_list\linked_list.py", line 24, in __getitem__
raise IndexError(f'Could not find index {value}')
IndexError: Could not find index 1
>>>
>>> ll.reverse() # Reverse the list in place, sorting nodes in descending order
>>> [n.value for n in ll]
[9, 5, 3]
>>> ll.reverse() # Restore the ascending order
>>> [n.value for n in ll]
[3, 5, 9]
>>>