Deletion of node from linkedlist

Question

I have created a linkedlist class with deletion method. I have written the code to delete the node no matter what situation it is, like

1. if deleting node is self.head
2. if only one node present in linkedlist
3. Any node from linked list

Code:

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None
        self.tail = None
        self.length = 0
    
    def __str__(self):
        temp_node = self.head
        result = ''
        while temp_node is not None:
            result += str(temp_node.value)
            if temp_node.next is not None:
                result += ' -> '
            temp_node = temp_node.next
        return result
    
    def append(self, value):
        new_node = Node(value)
        if self.head is None:
            self.head = new_node
            self.tail = new_node
        else:
            self.tail.next = new_node
            self.tail = new_node
        self.length += 1
        
    def get(self, index):
        temp_node = self.head
        if self.length == 1 or index == 0:
            return self.head
        else:
            for _ in range(index):
                temp_node = temp_node.next
            return temp_node
            
    def remove(self,index):
        if (index == 0):
            popped_node = self.head
            self.head = self.head.next
            return popped_node
        elif (self.length == 1):
            popped_node = self.head
            self.head = self.tail = None
            return popped_node
        else:
            temp_head = self.head
            for _ in range(index-1):
                temp_head = temp_head.next
            prev_node = temp_head
            popped_node = prev_node.next
            prev_node.next = popped_node.next
            popped_node.next = None
            return popped_node

but eventually it is giving below error

Error details 5 != 4 : Removing head node failed

What is the issue here?

Answer 1

In remove, you're not updating the length attribute, and except for one case you are not updating self.tail either (when the last node is removed).

Not a problem, but you don't need to distinguish the middle case with the else case.

Correction:

    def remove(self,index):
        if not (0 <= index < self.length):
            return  # Index out of range: ignore
        if index == 0:
            popped_node = self.head
            self.head = self.head.next
            if not self.head:
                self.tail = None  ## This was missing
        else:  # No need to deal with length==1 separately
            prev_node = self.head
            for _ in range(index-1):
                prev_node = prev_node.next
            popped_node = prev_node.next
            prev_node.next = popped_node.next
            if not prev_node.next:
                self.tail = prev_node  ## This was missing

        # Some code is common to both cases:
        popped_node.next = None
        self.length -= 1  ## This was missing
        return popped_node