Python Stack & Queue

The Python, you can implement a stack and a queue using various data structures and libraries. Here’s how to implement both a stack and a queue:

Stack:

A stack is a linear data structure that follows the Last-In, First-Out (LIFO) principle, meaning that the last element added is the first one to be removed.

1. Using Lists: You can implement a stack using Python lists by using the append() method to push elements onto the stack and the pop() method to remove elements from the top of the stack:

   stack = []

   # Push elements onto the stack
   stack.append(1)
   stack.append(2)
   stack.append(3)

   # Pop elements from the stack
   popped_element = stack.pop()
   print("Popped Element:", popped_element)

2. Using collections.deque: The collections module provides a deque (double-ended queue) data structure, which can be used to implement a stack with efficient push and pop operations:

   from collections import deque

   stack = deque()

   # Push elements onto the stack
   stack.append(1)
   stack.append(2)
   stack.append(3)

   # Pop elements from the stack
   popped_element = stack.pop()
   print("Popped Element:", popped_element)

Queue:

A queue is a linear data structure that follows the First-In, First-Out (FIFO) principle, meaning that the first element added is the first one to be removed.

1. Using Lists: You can implement a simple queue using Python lists by using the append() method to enqueue elements and the pop(0) method to dequeue elements:

   queue = []

   # Enqueue elements
   queue.append(1)
   queue.append(2)
   queue.append(3)

   # Dequeue elements
   dequeued_element = queue.pop(0)
   print("Dequeued Element:", dequeued_element)

2. Using collections.deque: The collections module also provides a deque that can be used to implement a queue. It offers efficient enqueue and dequeue operations:

   from collections import deque

   queue = deque()

   # Enqueue elements
   queue.append(1)
   queue.append(2)
   queue.append(3)

   # Dequeue elements
   dequeued_element = queue.popleft()
   print("Dequeued Element:", dequeued_element)

3. Using queue.Queue: The queue module provides the Queue class, which is a thread-safe queue implementation. It can be used for implementing a simple queue:

   import queue

   q = queue.Queue()

   # Enqueue elements
   q.put(1)
   q.put(2)
   q.put(3)

   # Dequeue elements
   dequeued_element = q.get()
   print("Dequeued Element:", dequeued_element)

Choose the implementation that best suits your needs based on your specific use case and requirements. If you need thread-safe queues, consider using the queue.Queue class. For basic stack and queue operations, using lists or collections.deque should suffice.