Top Python Interview Questions 2026

try:
    with open('file.txt', 'r') as f:
        data = f.read()
except FileNotFoundError:
    print('File not found')
except IOError:
    print('IO error')

import time
def timer(func):
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        print(time.time() - start)
        return result
    return wrapper
@timer
def slow_func():
    time.sleep(1)

def fib(n):
    a, b = 0, 1
    for _ in range(n):
        yield a
        a, b = b, a + b

class ManagedFile:
    def __init__(self, name):
        self.name = name
    def __enter__(self):
        self.file = open(self.name)
        return self.file
    def __exit__(self, exc_type, exc_val, tb):
        self.file.close()

from collections import OrderedDict
class LRUCache:
    def __init__(self, capacity):
        self.cache = OrderedDict()
        self.capacity = capacity
    def get(self, key):
        if key in self.cache:
            self.cache.move_to_end(key)
            return self.cache[key]
        return -1
    def put(self, key, value):
        if key in self.cache:
            self.cache.move_to_end(key)
        self.cache[key] = value
        if len(self.cache) > self.capacity:
            self.cache.popitem(False)

import asyncio, aiohttp
async def fetch(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as resp:
            return await resp.text()
async def main():
    tasks = [fetch(u) for u in urls]
    return await asyncio.gather(*tasks)
asyncio.run(main())

import threading
class Singleton:
    _instance = None
    _lock = threading.Lock()
    def __new__(cls):
        if cls._instance is None:
            with cls._lock:
                if cls._instance is None:
                    cls._instance = super().__new__(cls)
        return cls._instance