python decorator for class

最新推荐文章于 2022-03-08 19:48:08 发布

原创最新推荐文章于 2022-03-08 19:48:08 发布 · 436 阅读

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本文探讨了Python中将类作为装饰器的实践，通过具体代码示例展示了装饰器在函数调用前后如何进行操作，及其实现过程中的注意事项。

1. 描述

把类做成装饰器，暂时没感觉到有什么用。函数全部在@时就已经执行完了，main函数中调用函数显示未定义，只能打印@时函数执行完的结果

2. 代码

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


class First(object):
    print(' First begin...')

    def __init__(self, num, name):
        print('init begin...')
        self.num = num
        self.name = name
        print('num = %s' % num)
        print('init end...')

    def __call__(self, fun, *args, **kwargs):
        print('call begin...')
        print('num = %s' % self.num)
        self.fun = fun
        print('func = %s' % self.fun)
        print('name = %s' % self.name)
        print('call end...')
        print('return self.fun')
        return self.fun(self.name)


@First(100, 'tom')
def my_func(name):
    print('my_func define...')
    print('my_func name = %s' % name)
    print('my_func end...')
    return 'hello world'


if __name__ == '__main__':
    print('main begin...')
    print('my_func = %s' % my_func)
    print('main end...')

3. 输出
First begin...
init begin...
num = 100
init end...
call begin...
num = 100
func = <function my_func at 0x0000017FA78B8E18>
name = tom
call end...
return self.fun
my_func define...
my_func name = tom
my_func end...
main begin...
my_func = hello world
main end...

Process finished with exit code 0