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Python Linked List: Access a specific item in a singly linked list using index value

Python Linked List: Exercise-4 with Solution

Write a Python program to access a specific 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


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("Search using index:")
print(items[0])
print(items[1])
print(items[4])
print(items[5])
print(items[10])

Sample Output:

Search using index:
PHP
Python
Java
Index out of range
Index out of range

Flowchart:

Flowchart: Access a specific item in a singly linked list using index value.

Python Code Editor:

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Previous: Write a Python program to search a specific item in a singly linked list and return true if the item is found otherwise return false.
Next: Write a Python program to set a new value of an item in a singly linked list using index value.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m