Python学习

1、@waps

　　保证被装饰函数所有的属性保持不变

from functools import wraps
def wrapper(func):
    @wraps(func)
    def inner(*args,**kwargs):
        print('在被装饰的函数执行之前做的事')
        ret = func(*args,**kwargs)
        print('在被装饰的函数执行之后做的事')
        return ret
    return inner

@wrapper
def holiday(day):
    '''This is a holiday notice'''
    print('元旦放假剩余%d天'%day)
    return('好开心噻！')

ret = holiday(3)
print(ret)

print(holiday.__name__)
print(holiday.__doc__)

2、带参数的装饰器

　　常用于批量处理装饰器函数的应用与否

import time
flage = True

def wrapper_out(flag):
    def wrapper(func):
        def inner(*args,**kwargs):
            if flag:
                start = time.time()
                ret = func(*args,**kwargs)
                end = time.time()
                print(end - start)
                return ret
            else:
                ret = func(*args, **kwargs)
                return ret
        return inner
    return wrapper

@wrapper_out(flage)
def wahaha():
    time.sleep(0.1)
    print('哇哈哈！')
@wrapper_out(flage)
def qqxing():
    time.sleep(0.1)
    print('QQ星！')

wahaha = wahaha()
print(wahaha)
qqxing = qqxing()
print(qqxing)

3、多个装饰器装饰同一个函数

　　俄罗斯套娃

　　

def wrapper1(func):
    def inner(*args,**kwargs):
        print('wrapper1函数装饰被装饰函数之前的函数')
        ret = func(*args,**kwargs)
        print('wrapper1函数装饰被装饰函数之后的函数')
        return ret
    return inner

def wrapper2(func):
    def inner(*args,**kwargs):
        print('wrapper2函数装饰被装饰函数之前的函数')
        ret = func(*args,**kwargs)
        print('wrapper2函数装饰被装饰函数之后的函数')
        return ret
    return inner

@wrapper2
@wrapper1
def func():
    print('被执行的函数')
    return('小混蛋骂谁？')

ret = func()
print(ret)