python学习day13

Posted 2020-10-06

 

 

带参数的装饰器

FLAG = False
def log(flag):
    def wrapper(func):
        def inner(*args,**kwargs):
            if flag:
                print(‘call : %s‘%func.__name__)
            ret = func(*args,**kwargs)
            return ret
        return inner
    return wrapper

@log(FLAG)  #wrapper = log(FlAG)   --> @wrapper --> qqxing = wrapper(qqxing) = inner
def qqxing():
    print(‘qqxing‘)

qqxing()  #inner()

此例子可以不改变装饰器的内容，仅通过改变全局变量来决定是否启用这个装饰器

 

装饰器嵌套

def wrapper1(func):
    def inner1():
        print(‘wrapper1 ,before func‘)
        func()  #f
        print(‘wrapper1 ,after func‘)
    return inner1

def wrapper2(func):
    def inner2():
        print(‘wrapper2 ,before func‘)
        func()   #inner1
        print(‘wrapper2 ,after func‘)
    return inner2

@wrapper2  #f = wrapper2(wrapper1(f))  --> f = wrapper2(inner1)   -->   f = inner2
@wrapper1
def f():
    print(‘in f‘)

f()