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Python Linked List: Set a new value of an item in a singly linked list using index value

Python Linked List: Exercise-5 with Solution

Write a Python program to set a new value of an item in a singly linked list using index value.

Sample Solution:-

Python Code:

class Node:
    # Singly linked node
    def __init__(self, data=None):
        self.data = data
        self.next = None
class singly_linked_list:
    def __init__(self):
        # Createe an empty list
        self.tail = None
        self.head = None
        self.count = 0

    def append_item(self, data):
        #Append items on the list
        node = Node(data)
        if self.head:
            self.head.next = node
            self.head = node
        else:
            self.tail = node
            self.head = node
        self.count += 1
    
    def __getitem__(self, index):
        if index > self.count - 1:
            return "Index out of range"
        current_val = self.tail
        for n in range(index):
            current_val = current_val.next
        return current_val.data
    
    def __setitem__(self, index, value):
        if index > self.count - 1:
            raise Exception("Index out of range.")
        current = self.tail
        for n in range(index):
            current = current.next
        current.data = value

items = singly_linked_list()
items.append_item('PHP')
items.append_item('Python')
items.append_item('C#')
items.append_item('C++')
items.append_item('Java')

print("Modify items by index:")
items[1] ="SQL"
print("New value: ",items[1])
items[4] ="Perl"
print("New value: ",items[4])

Sample Output:

Modify items by index:
New value:  SQL
New value:  Perl

Flowchart:

Flowchart: Set a new value of an item in a singly linked list using index value.

Python Code Editor:

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Python: Tips of the Day

Creates a dictionary with the same keys as the provided dictionary and values generated by running the provided function for each value:

Example:

def tips_map_values(obj, fn):
  ret = {}
  for key in obj.keys():
    ret[key] = fn(obj[key])
  return ret
users = {
  'Owen': { 'user': 'Owen', 'age': 29 },
  'Eddie': { 'user': 'Eddie', 'age': 15 }
}

print(tips_map_values(users, lambda u : u['age'])) # {'Owen': 29, 'Eddie': 15}

Output:

{'Owen': 29, 'Eddie': 15}