层层深入python装饰器

忘是亡心i 2024-04-18 08:19 69阅读 0赞

# 一、内部函数 #

def outer():
        def inner():
            x = 10

# 二、闭包 #

n = 'hello'
    def outer(arg):
        def inner():
            arg
        return inner
    f = outer(n)

# 三、装饰器： #

### 原始方式 ###

def n():
        print("hello world")
    def outter(arg):
        def inner():
            print("*" * 20)
            arg()
          return inner
    n = outer(n)
    n()

### 语法糖 ###

def outter(arg):
        def inner():
            print("*" * 20)
            arg()
          return inner
    def n():
        print("hello world")
    @outer
    n()

# 四、装饰器固定格式 #

def auth(func):
        def wrapper(*args,**kwargs):
            # 写需要增加的代码
            r = func(*args,**kwargs)
            return r
        return wrapper
    
    @auth
    def foo(msg):
        up_msg = msg.upper()
        return up_msg
    r = foo('hello')
    print(r)

# 五、带参的装饰器 #

def outer(falg):
        def wrapper(func):
            def inner(*args, **kwargs):
                if flag:
                    print('before')
                    result = func(*args,**kwargs)
                    print('after')
                else:
                    result = func(*args, **kwargs)
                return result
            return inner
        return wrapper

# 六、多层装饰器 #

def do_something(arg):
        def wrapper():
            print('#' * 22)
            arg()
            print('#' * 22)
        return wrapper
    
    
    def decorator(func):
        def wrapper():
            print("*" * 19)
            func()
            print("*" * 19)
        return wrapper
    
    do_something(decorator)
    
    @do_something   # inner = do_something(decorator(inner))
    @decorator      
    def inner():
        print("  hello world")
        print("   单车欲问边，蜀国过居延")
    
    inner()

# eg.计算一个程序运行所需时间 #

import time
    
    def timeit(func):
        def test():
            start = time.clock()
            func()
            end = time.clock()
            print("time used:", end - start)
        return test
    
    @timeit
    def sum():
        sum = 1+2
        print(sum)
    
    sum()