12. Advanced decorator

When executing the function* break up

When defining a function* aggregate

from functools import wraps
def wrapper(f):  # f = func1
    @wraps(f)
    def inner(*args,**kwargs): #Aggregate
        #args （1,2,3）
        '''Relevant operations before executing the function'''
        ret = f(*args,**kwargs) # break up 1,2,3
        '''Relevant operations after executing the function'''
        return right
    return inner
# When the function is executed, * is scattered.
# When the function is defined, *aggregate.
@wrapper  # func1 = wrapper(func1)  func1 = inner
def func1(*args): #args (1,2,3)
    print(666)
    return args
print(func1(*[1,2,3])) # inner(1,3,5) Disperse 

useful information of print function

@wrapper     def 
func1():     "     " 
    "     This 
    function is the function to complete the login, the parameters are... func1() print(func1.__name__) print(func1.__doc__)

#666
 func1

 This function is the function of completing the login, and the parameters are ... functions.
: return: The return value is whether the login is successful or not (True, False)

Decorator with parameters

import time
def timmer(*args,**kwargs):
    def wrapper(f):
        def inner(*args,**kwargs):
            if flag:
                start_time = time.time()
                ret = f(*args,**kwargs)
                time.sleep(0.3)
                end_time = time.time()
                print('此函数的执行效率%f' % (end_time-start_time))
            else:
                ret = f(*args, **kwargs)
            return ret
        return inner
    return wrapper

flag = False
@timmer(flag,2,3)  # 两步：1，timmer(flag) --> wrapper 2,@wrapper 装饰器
def func1():
    print(666)


@timmer(flag)
def func2():
    print(777)
func1()
func2()

多个装饰器装饰一个函数

def wrapper1(func): f = func
    def inner1():
        print('wrapper1 ,before func')
        func()
        print('wrapper1 ,after func')
    return inner1

def wrapper2(func):  func = inner1
    def inner2():
        print('wrapper2 ,before func')
        func()
        print('wrapper2 ,after func')
    return inner2

@wrapper2   然后读@wrapper2   f = inner2   
@wrapper1   先读@wrapp1      f = inner1
def f():
    print('in f')

f()        再读f()