python 装饰器

一、无参数，无返回值的装饰器

def check(func):
    def inner():
        print('def')
        func()
    return inner

@check    #foo = check(foo)
def foo():
    print('abc')
   
foo()

二、2个装饰器

# -*- coding:utf-8 -*-

def check(func):
    def inner():
        print('def')
        func()
    return inner

def check1(func):
    def inner():
        print('ghk')
        func()
    return inner

@check    #foo = check(foo)   后装饰，先执行
@check1   #foo = check1(foo)  先装饰，后执行
def foo():
    print('abc')

foo()

结果：

def
ghk
abc

三、带参数，无返回值函数的装饰器

# -*- coding:utf-8 -*-

def check(func):
    def inner(arg):
        print('def')
        func(arg)
    return inner

@check    #foo = check(foo)
def foo(arg):
    print('abc%s' % arg)

foo('d')

四、带参数，带返回值函数的装饰器

# -*- coding:utf-8 -*-

def check(func):
    def inner(arg):
        print('def')
        ret = func(arg)
        print('ghk')
        return ret
    return inner

@check    #foo = check(foo)
def foo(arg):
    print('abc%s' % arg)
    return 'ok'

ret = foo('d')
print(ret)

五、通用的装饰器

# -*- coding:utf-8 -*-

def check(func):
    def inner(*args, **kwargs):
        print('...')
        ret = func(*args, **kwargs)
        print('---')
        return ret
    return inner

@check    #foo = check(foo)
def foo(arg):
    print('abc%s' % arg)
    return 'ok'

ret = foo('d')
print(ret)

六、装饰器带参数

# -*- coding:utf-8 -*-

def outter(arg):
    def check(func):
        def inner(*args, **kwargs):
            print(arg)
            print('...')
            ret = func(*args, **kwargs)
            print('---')
            return ret
        return inner
    return check

@outter('e')    #先执行outter('e')，再装饰foo = check(foo)
def foo(arg):
    print('abc%s' % arg)
    return 'ok'

ret = foo('d')
print(ret)

结果：

e
...
abcd
---
ok