When it is required to find the number of occurences of all the elements of a linked list, a method to add elements to the linked list, a method to print the elements and a method to find the occurrence of all elements in the linked list are defined.
Below is a demonstration for the same −
Example
class Node:
def __init__(self, data):
self.data = data
self.next = None
class LinkedList_structure:
def __init__(self):
self.head = None
self.last_node = None
def add_vals(self, data):
if self.last_node is None:
self.head = Node(data)
self.last_node = self.head
else:
self.last_node.next = Node(data)
self.last_node = self.last_node.next
def print_it(self):
curr = self.head
while curr:
print(curr.data)
curr = curr.next
def count_elem(self, key):
curr = self.head
count_val = 0
while curr:
if curr.data == key:
count_val = count_val + 1
curr = curr.next
return count_val
my_instance = LinkedList_structure()
my_list = [56, 78, 98, 12, 34, 55, 0]
for elem in my_list:
my_instance.add_vals(elem)
print('The linked list is : ')
my_instance.print_it()
key_val = int(input('Enter the data item '))
count_val = my_instance.count_elem(key_val)
print('{0} occurs {1} time(s) in the list.'.format(key_val, count_val))Output
The linked list is : 56 78 98 12 34 55 0 Enter the data item 0 0 occurs 1 time(s) in the list.
Explanation
The ‘Node’ class is created.
Another ‘LinkedList_structure’ class with required attributes is created.
It has an ‘init’ function that is used to initialize the first element, i.e the ‘head’ to ‘None’.
A method named ‘add_vals’ is defined, that helps add a value to the stack.
Another method named ‘print_it’ is defined, that helps display the values of the linked list on the console.
Another method named ‘count_elem’ is defined, that helps find the occurrence of every character in the linked list.
An instance of the ‘LinkedList_structure’ is created.
A list of elements is defined.
The list is iterated over, and these elements are added to the linked list.
The elements are displayed on the console.
The ‘count_elem’ method is called on this linked list.
The output is displayed on the console.