Python/data_structures/linked_list/print_reverse.py
Hanif Ali 4c37eb7d07 Improved on Singly Linked List Programs (#1558)
* Improved Singly Linked List
Added String Representations of Nodes and Linked Lists
Added support for indexing and changing of Node data using indices.

* Added a few comments to Linked Lists

* Reformatted to conform to PEP8

* Added from_sequence.py
Convert a Python List to Linked List comprising of Nodes and return head.

* Added print_reverse.py
Recursive program to print the elements of a Linked List in reverse.

* Change 'is not None' for more Pythonicness
2019-11-10 09:47:04 +01:00

56 lines
1.4 KiB
Python

# Program to print the elements of a linked list in reverse
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
def __repr__(self):
"""Returns a visual representation of the node and all its following nodes."""
string_rep = ""
temp = self
while temp:
string_rep += f"<{temp.data}> ---> "
temp = temp.next
string_rep += "<END>"
return string_rep
def make_linked_list(elements_list):
"""Creates a Linked List from the elements of the given sequence
(list/tuple) and returns the head of the Linked List."""
# if elements_list is empty
if not elements_list:
raise Exception("The Elements List is empty")
# Set first element as Head
head = Node(elements_list[0])
current = head
# Loop through elements from position 1
for data in elements_list[1:]:
current.next = Node(data)
current = current.next
return head
def print_reverse(head_node):
"""Prints the elements of the given Linked List in reverse order"""
# If reached end of the List
if head_node is None:
return None
else:
# Recurse
print_reverse(head_node.next)
print(head_node.data)
list_data = [14,52,14,12,43]
linked_list = make_linked_list(list_data)
print("Linked List:")
print(linked_list)
print("Elements in Reverse:")
print_reverse(linked_list)