Python 装饰器

def say():
    print("zutuanxue_com is a good man")

def newSay():
    print("**************")
    say()

newSay()

# 参数f：要给哪个函数增加功能，那么就在调用wrapper()函数时传递那个函数
def wrapper(f):
    # inner()函数即为替代版函数，要实现原函数的功能，并增加新功能
    def inner():
        # 在原函数基础上增加新的功能
        print("*************")
        # 实现原函数功能
        res = f()
        return res
    return inner

def say():
    print("zutuanxue_com is a good man")

# newSay = wrapper(say)
# newSay()

say = wrapper(say)
say()

def wrapper(f):
    # 原函数的参数在inner函数这里传递
    def inner(name, age):
        # 增加的判断age的功能
        if age < 0:
            age = 0
        res = f(name, age)
        return res
    return inner

def say(name, age):
    return "%s is a good man!He is %d years old!"%(name, age)

say = wrapper(say)
# 增加判断年龄如果小于0，则打印0即可
print(say("zutuanxue_com", -18))

def wrapper1(f):
    def inner(name, age):
        if age < 0:
            age = 0
        res = f(name, age)
        return res
    return inner
def wrapper2(f):
    def inner(name, age, height):
        if age < 0:
            age = 0
        res = f(name, age, height)
        return res
    return inner
def wrapper3(f):
    def inner(name, age, *args, **kwargs):
        if age < 0:
            age = 0
        res = f(name, age, *args, **kwargs)
        return res
    return inner
  
  
def say1(name, age):
    return "%s is a good man!He is %d years old!"%(name, age)

def say2(name, age, height):
    return "%s is a good man!He is %d years old!His height is %.2f"%(name, age, height)

#装饰函数
say1 = wrapper3(say1)
say2 = wrapper3(say2)
print(say1("zutuanxue_com", -19))
print(say2("kaige", -20, 173.55))

#给函数增加打印一串星号的功能，通用所有函数
def wrapper(f):
    def inner(*args, **kwargs):
        print("*************")
        res = f(*args, **kwargs)
        return res
    return inner

def wrapper(f):
    def inner():
        print("*************")
        res = f()
        return res
    return inner

@wrapper  #相当于   say = wrapper(say)
def say():
    print("zutuanxue_com is a good man")

say()

# 接收装饰器传递的参数
def wrapper(count=3):
    # 接收带添加功能的函数
    def deco(f):
        # 接收原函数的参数
        def inner(*args, **kwargs):
            for i in range(count):
                f(*args, **kwargs)
        return inner
    return deco

# 没有参数传递，也需要带着小括号
@wrapper()
def say(name, age):
    print("%s is a good man!He is %d years old!"%(name, age))

say("zutuanxue_com", 18)

def wrapper1(f):
    def inner1(*args, **kwargs):
        print("enter inner1")
        res = f(*args, **kwargs)
        print("exit inner1")
        return res
    return inner1
def wrapper2(f):
    def inner2(*args, **kwargs):
        print("enter inner2")
        res = f(*args, **kwargs)
        print("exit inner2")
        return res
    return inner2
def wrapper3(f):
    def inner3(*args, **kwargs):
        print("enter inner3")
        res = f(*args, **kwargs)
        print("exit inner3")
        return res
    return inner3

'''
装饰时：从距离近的装饰器开始装饰
执行时：从距离远的装饰器内部函数开始执行
'''
@wrapper1
@wrapper2
@wrapper3
def say():
    print("zutuanxue_com is a good man")
    
'''
say = wrapper3(say)
say = wrapper2(say)
say = wrapper1(say)
---------------------------
inner3 = wrapper3(say)
say = inner3
inner2 = wrapper2(inner3)
say = inner2
inner1 = wrapper1(inner2)
say = inner1
'''
print("-------------------------")
say()

def wrapper(f):
    count = 1
    def inner(*args, **kwargs):
        nonlocal count
        print("第%d次执行"%(count))
        res = f(*args, **kwargs)
        count += 1
        return res
    return inner

@wrapper
def say():
    print("zutuanxue_com is a good man")

say()
say()
say()

import time

def wrapper(f):
    def inner(*args, **kwargs):
        t1 = time.time() #获取当前时间的时间戳
        res = f()
        t2 = time.time()
        print("耗时%.2f秒"%(t2-t1))
        return res
    return inner

@wrapper
def say():
    print("zutuanxue_com is a good man")
    # 休息2秒钟，可以是浮点数
    time.sleep(2)
    print("zutuanxue_com is a nice man")

say()

import random
import time

def retry(count=3, wait=0, exceptions=(Exception,)):
    def deco(f):
        def inner(*args, **kwargs):
            for i in range(count):
                try:
                    res = f(*args, **kwargs)
                    return res
                except exceptions as e:
                    if not (i == count - 1):
                        time.sleep(wait)
            return -1 #这里用的表示失败的值一定不能出现在成功中
        return inner
    return deco

@retry()
def func():
    num = random.choice([1,2,3,4])
    if num <= 2:
        num / 0
    else:
        print("********************", num)

if func() == -1:
    print("程序运行出错")