Python Linked List Class

This structure covers the main aspects of linked list implementation

## Short methods description

1. __str__

   • Returns a string representation of the list in the format: value1 -> value2 -> value3. If the list is empty, returns "Empty List".

2. __iter__(return_node: bool = False)

   • Returns an iterator to traverse the list. If return_node=True, returns Node objects, otherwise returns the node values.

3. __len__

   • Returns the length of the list.

4. clear()

   • Clears the list by removing all elements.

5. add(value) -> bool

   • Adds an element to the end of the list. Returns True upon successful addition.

6. pop() -> Optional[Any]

   • Removes and returns the last element of the list. If the list is empty, returns None.

7. delete_by_first_appeared_value(value) -> bool

   • Removes the first element found with the specified value. Returns True if the element is found and removed, otherwise False.

8. search_by_index(index, return_node=False) -> Node | Any

   • Returns the element by index. If return_node=True, returns the Node object, otherwise returns the node value.

9. insert_at_index(index: int, value) -> bool

   • Inserts an element with the specified value at the given index. Returns True upon successful insertion.

10. delete_by_index(index) -> bool

    • Removes the element by index. Returns True if the element is successfully removed, otherwise raises an IndexError.

11. to_list() -> List[Any]

    • Converts the list to a Python List and returns it.

12. reverse()

    • Reverses the list, creating a new list with elements in reverse order.

13. contains(value) -> bool

    • Checks if the list contains an element with the specified value. Returns True or False.

14. index_of(value) -> int

    • Returns the index of the first element found with the specified value. If the element is not found, returns None.

15. is_empty() -> bool

    • Checks if the list is empty. Returns True if the list is empty, otherwise False.

16. extend(values: List[Any]) -> None

    • Adds elements from the given List to the end of the current list.

17. count(value) -> int

    • Returns the number of occurrences of an element with the specified value in the list.

18. reverse_in_place()

    • Reverses the list in place, changing the order of elements without creating a new list.

19. copy() -> LinkedList

    • Creates and returns a copy of the current list.

20. merge(list: LinkedList) -> None

    • Merges the current list with another LinkedList object. Raises a TypeError if the passed object is not an instance of LinkedList.

21. delete_all_occurances_by_value(value) -> None

    • Removes all elements with the specified value from the list.

Usage

from linked_list import LinkedList

# Create a new linked list
ll = LinkedList()

# Add elements
ll.add(10)
ll.add(20)
ll.add(30)

# Print the list
print(ll)

# Get the length of the list
print(len(ll))

# Check if the list contains a value
print(ll.contains(20))

# Remove an element by value
ll.delete_by_first_appeared_value(20)

# Convert to a Python list
print(ll.to_list())

# Reverse the list
ll.reverse()

# Print the reversed list
print(ll)

To run the tests, execute from the folowing command

python -m linked_list_unittest