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

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

First, create two nodes temp and nodeToDelete to traverse through the list and track the node to delete respectively. After that count the number of elements in the list to check whether the specified position is valid or not (It must lie in the range of [1, n], where n is number of elements in the list). If the specified valid position is 1 and head is the only element in the list, then make the head as null. If the specified valid position is 1 and list contains more than one elements, then make next of head as new head and adjust links accordingly. If the specified valid position is greater than 1 then traverse to the node previous to the given position and delete the given node and adjust links accordingly. The function pop_at is created for this purpose. It is a 5-step process.

```def pop_at(self, position):

#1. create two nodes - temp and nodeToDelete
#   to traverse and track the node to delete
NoOfElements = 0

#2. Find the number of elements in the list
if(temp != None):
NoOfElements += 1
temp = temp.next
NoOfElements += 1
temp = temp.next

#3. check if the specified position is valid
if(position < 1 or position > NoOfElements):
print("\nInavalid position.")
elif (position == 1):

#4. if the position is 1 and head is the only element
#   in the list, then make it null, else make next
else:
temp = temp.next
nodeToDelete = None

else:

#5. Else, traverse to the node previous to
#   the given position and delete the given
for i in range(1, position-1):
temp = temp.next
nodeToDelete = temp.next
temp.next = temp.next.next
temp.next.prev = temp
nodeToDelete = None
```

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

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

def __init__(self):

#Add new element at the end of the list
def push_back(self, newElement):
newNode = Node(newElement)
return
else:
temp = temp.next
temp.next = newNode
newNode.prev = temp

#Delete an element at the given position
def pop_at(self, position):
NoOfElements = 0

if(temp != None):
NoOfElements += 1
temp = temp.next
NoOfElements += 1
temp = temp.next

if(position < 1 or position > NoOfElements):
print("\nInavalid position.")
elif (position == 1):
else:
temp = temp.next
nodeToDelete = None

else:
for i in range(1, position-1):
temp = temp.next
nodeToDelete = temp.next
temp.next = temp.next.next
temp.next.prev = temp
nodeToDelete = None

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

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