How do I implement a stack and a queue in Python?

How do I implement a stack and a queue in Python?

You can implement a stack using a list and the append/pop methods. For a queue, you can use collections.deque for efficiency.

Can you show me a simple code example for both?

Sure! Here's a simple stack implementation:

class Stack:
    def __init__(self):
        self.items = []
    
    def push(self, item):
        self.items.append(item)
    
    def pop(self):
        return self.items.pop() if not self.is_empty() else None
    
    def is_empty(self):
        return len(self.items) == 0

And for a queue:

from collections import deque

class Queue:
    def __init__(self):
        self.items = deque()
    
    def enqueue(self, item):
        self.items.append(item)
    
    def dequeue(self):
        return self.items.popleft() if not self.is_empty() else None
    
    def is_empty(self):
        return len(self.items) == 0

What are the main differences between stack and queue?

The main difference is in how they handle data: a stack is LIFO (Last In, First Out) while a queue is FIFO (First In, First Out).