remove a node from the middle of a linked list in python

To remove a node from the middle of a linked list, you must first find the node that you wish to remove, and then modify the previous node to point to the next node. This can be done in the following way:

main.py
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None
        
def remove_node(head, value):
    if head is None:
        return head
    
    # if node to be removed is the head node
    if head.data == value:
        return head.next
    
    # get the previous node of the node to be removed
    prev = head
    while prev.next is not None:
        if prev.next.data == value:
            break
        prev = prev.next
        
    # remove the node
    if prev.next is not None:
        prev.next = prev.next.next
    
    return head
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In this example, we define a Node class that has a data attribute and a next attribute, which is the next node in the linked list. We also define a remove_node function that takes a head node and a value to be removed.

In the function, we first check if the linked list is empty or if the node to be removed is the head node. If it is the head node, we simply return the next node. Otherwise, we traverse the linked list to find the previous node of the node to be removed.

Once we have the previous node, we simply set its next attribute to the next attribute of the node to be removed, effectively removing it from the linked list.

Finally, we return the head node, which may have changed if the head node was removed.