python装饰器的理解+顺序

def log(func):
    def wrapper(*args,**kwargs):
        return func(*args,**kwargs)
    return wrapper

@log
def f():
    ···

相当于执行log(f)
如果有参数log('参数')(f)=== wrapper(f)

def decorator_a(func):
    print 'Get in decorator_a'
    def inner_a(*args,**kwargs):
        print 'Get in inner_a'
        return func(*args,**kwargs)
    return inner_a

def decorator_b(func):
    print 'Get in decorator_b'
    def inner_b(*args,**kwargs):
        print 'Get in inner_b'
        return func(*args,**kwargs)
    return inner_b

@decorator_b
@decorator_a
def f(x):
    print 'Get in f'
    return x*2
f(1)

装饰器其实在定义的时候就执行了decorator_a,decorator_b(顺序为从下到上)所以会先打印出get in decorator_a,和get in decoator_b 然后此时函数f已经变成了innerb,===inner_b(inner_a(f))当去调用f(1)的时候，会打印出get in inner_a,然后去调用inner_a，打印出 get in inner_a ,然后调用f 打印出 get in f,结束