python其他用法

Lambda

• map(function, iterable)：将指定的函数应用在列表的每个元素上，并返回一个新的序列

  list1 = (1,2,3)
  xxx= map(lambda x: x**2, list1) # 算每个元素的平方
  print(list(xxx))   # [1, 4, 9]
  

• filter(function, iterable)：将指定的函数应用在列表的每个元素上，并返回一个新的序列

  numbers = [1, 2, 3, 4]
  xxx= filter(lambda x : x%2 ==0 ,numbers) # 过滤出为True的元素
  print(list(xxx))
  

推导式

• 列表推导式

  result = [x for x in list1 if x not in set(list2)] # 在list1中但不在list2中的元素
  
  names = ['Bob','Tom','alice','Jerry','Wendy','Smith']
  new_names = [name.upper() for name in names if len(name)>3] # 找到名字长度大于3的，并转为大写
  

• 元组推导式

  a = (x for x in range(1,3))
  tuple(a) 
  

多线程

import threading
import time

def task(thread_name, delay):
    print(f"Thread {thread_name} is starting...")
    time.sleep(delay)
    print(f"Thread {thread_name} is finished.")

if __name__ == '__main__':
    # 创建线程
    threads = []
    for i in range(5):
        thread = threading.Thread(target=task, args=(f"Thread-{i}", i))  # args为传参
        threads.append(thread)
        thread.start()

    # 等待所有线程结束
    for thread in threads:
        thread.join()

    print("All threads have finished.")

装饰器

from functools import wraps

def logger(func):
    @wraps(func)
    def decorated(*args, **kwargs):
        return func(*args, **kwargs)
    return decorated

@logger
def addition_func(x):
    return x + x

print(addition_func(4))  # 输出8