别再写脚本了!用好这3个Python高阶特性,让你的代码优雅10倍

def my_decorator(func):def wrapper():print("执行前")func()  # 调用原函数print("执行后")return wrapper@my_decoratordef say_hello():print("你好")say_hello()

执行前你好执行后

import timefrom functools import wrapsdef timer(func):@wraps(func)  # 这行很重要！保留原函数信息def wrapper(args, *kwargs):start = time.time()result = func(args, *kwargs)print(f"{func.name} 耗时：{time.time() - start:.2f}秒")return resultreturn wrapper@timerdef slow_function():time.sleep(1)print("执行完毕")slow_function()

执行完毕slow_function 耗时：1.00秒

def retry(max_attempts=3, delay=1):def decorator(func):@wraps(func)def wrapper(args, *kwargs):for attempt in range(1, max_attempts + 1):try:return func(args, *kwargs)except Exception as e:if attempt == max_attempts:raiseprint(f"第{attempt}次失败，{delay}秒后重试...")time.sleep(delay)return wrapperreturn decorator@retry(max_attempts=3, delay=2)def fetch_data():pass

def bad_decorator(func):def wrapper():func()return wrapper@bad_decoratordef test():"""这是测试函数的文档"""passprint(test.name)  # 输出：wrapper ❌print(test.doc)   # 输出：None ❌from functools import wrapsdef good_decorator(func):@wraps(func)def wrapper():func()return wrapper@good_decoratordef test2():"""这是测试函数的文档"""passprint(test2.name)  # 输出：test2 ✅print(test2.doc)   # 输出：这是测试函数的文档 ✅

lst = [x*2 for x in range(1000000)]  # 占用大量内存gen = (x*2 for x in range(1000000))  # 仅创建生成器对象

def countupto(max_num):count = 1while count <= max_num:yield countcount += 1for num in countupto(5):print(num)  # 1, 2, 3, 4, 5

def readlargefile(filepath):"""内存友好的大文件读取"""with open(filepath, 'r') as f:for line in f:yield line.strip()for line in readlargefile('huge_log.txt'):process(line)  # 每次只处理一行

f = open("test.txt", "r")data = f.read()f.close()with open("test.txt", "r") as f:data = f.read()

class FileManager:def init(self, filename, mode):self.filename = filenameself.mode = modeself.file = Nonedef enter(self):self.file = open(self.filename, self.mode)return self.filedef exit(self, exctype, excval, exc_tb):if self.file:self.file.close()return False  # 不抑制异常with FileManager("example.txt", "w") as f:f.write("Hello, World!")

from contextlib import contextmanagerimport time@contextmanagerdef timer(name):start = time.time()yieldprint(f"{name} 耗时: {time.time() - start:.2f}秒")with timer("数据处理"):pass

from contextlib import contextmanagerimport sqlite3@contextmanagerdef transaction(db_path):conn = sqlite3.connect(db_path)try:yield connconn.commit()except Exception:conn.rollback()raisefinally:conn.close()with transaction('app.db') as conn:cursor = conn.cursor()cursor.execute('UPDATE users SET name=? WHERE id=?', ('Alice', 1))

@timer@retry(max_attempts=3)def fetch_page(url):with open('cache.txt', 'r') as f:return f.read()