Python - Delete a node at the given position in the Linked List

In this method, a node at the specified position in the linked list is deleted. For example - if the given List is 10->20->30 and the 2nd node is deleted, the Linked List becomes 10->20.

First, the specified position must be greater than equal to 1. If the specified position is 1 and head is not null, then make the head next as head and delete the previous head. Else, traverse to the node that is previous to the specified position. If the specified node and previous to the specified node are not null then adjust the link. In other case, the specified node will be already null. The below figure describes the process, if the deletion node is other than the head node. The function pop_at is created for this purpose. It is a 5-step process.

def pop_at(self, position):

#1. check if the position is > 0
if(position < 1):
print("\nposition should be >= 1.")
elif (position == 1 and self.head != None):

#2. if the position is 1 and head is not null, make
nodeToDelete = None
else:

#3. Else, make a temp node and traverse to the
#   node previous to the position
for i in range(1, position-1):
if(temp != None):
temp = temp.next

#4. If the previous node and next of the previous
if(temp != None and temp.next != None):
nodeToDelete = temp.next
temp.next = temp.next.next
nodeToDelete = None
else:

#5. Else the given node will be empty.

The below is a complete program that uses above discussed concept to delete a node at a given position in the linked list.

# node structure
class Node:
def __init__(self, data):
self.data = data
self.next = None

def __init__(self):

#Add new element at the end of the list
def push_back(self, newElement):
newNode = Node(newElement)
return
else:
while(temp.next != None):
temp = temp.next
temp.next = newNode

#Delete an element at the given position
def pop_at(self, position):
if(position < 1):
print("\nposition should be >= 1.")
elif (position == 1 and self.head != None):
nodeToDelete = None
else:
for i in range(1, position-1):
if(temp != None):
temp = temp.next
if(temp != None and temp.next != None):
nodeToDelete = temp.next
temp.next = temp.next.next
nodeToDelete = None
else:

#display the content of the list
def PrintList(self):
if(temp != None):
print("The list contains:", end=" ")
while (temp != None):
print(temp.data, end=" ")
temp = temp.next
print()
else:
print("The list is empty.")

# test the code

#Add three elements at the end of the list.
MyList.push_back(10)
MyList.push_back(20)
MyList.push_back(30)
MyList.PrintList()

#Delete an element at position 2
MyList.pop_at(2)
MyList.PrintList()

#Delete an element at position 1
MyList.pop_at(1)
MyList.PrintList()

The above code will give the following output:

The list contains: 10 20 30
The list contains: 10 30
The list contains: 30

5