Python的闭包和装饰器你真的了解吗

闭包

闭包就是能够读取其他函数内部变量的函数。

def test1(k, b):
   def test1_1(x):
       print(k*x+b)
   return test1_1
t1 = test1(1, 2)
t1(0)
t1(1)
t1(2)

闭包中修改数据

x = 300
def test1():
   x = 200
   def test2():
       nonlocal x
       print("----1----x = {}".format(x))
       x = 100
       print("----2----x = {}".format(x))
   return test2
t1 = test1()
t1()

装饰器

实现对无参数函数的装饰器

def set_func(func):
   def call_func():
       print("装饰器执行")
       func()
   return call_func
@set_func   # 等价于sumNum = set_func(sumNum)
def sumNum():
   print("sumNum")
sumNum()

实现对有参数函数的装饰器

# 对有参数、无返回值的函数进行装饰
def set_func(func):
   def call_func(num):
       print("装饰器")
       func(num)
   return call_func
@set_func
def sumNum(num):
   print("sumNum = {}".format(num))
sumNum(100)

对不定长参数的函数进行装饰

def set_func(func):
   def call_func(*args, **kwargs):
       print("装饰器")
       func(*args, **kwargs)  # 拆包
   return call_func
@set_func
def sumNum(num, *args, **kwargs):
   print("sumNum = {}".format(num))
   print("args = {}".format(args))
   print("kwargs = {}".format(kwargs))
sumNum(100, 200, c=100)

对有返回值的函数进行装饰

def set_func(func):
   def call_func(*args, **kwargs):
       print("装饰器")
       return func(*args, **kwargs)  # 拆包
   return call_func
@set_func
def sumNum(num, *args, **kwargs):
   print("sumNum = {}".format(num))
   print("args = {}".format(args))
   print("kwargs = {}".format(kwargs))
   return "200 ok"
sumNum(100, 200, c=100)

多个装饰器对同一个函数装饰

def add_h1(func):
   def h1():
       h1_str = "<h1>" + func() + "</h1>"
       return h1_str
   return h1

def add_a(func):
   def call_func():
   a_str = "<a>" + func() + "</a>"
       return a_str
   return call_func

@add_h1
@add_a
def get_str():
   return "haha"
get_str()

输出为：<h1><a>haha</a></h1>

来源：https://blog.csdn.net/weixin_43670190/article/details/122916070