python 装饰器
1.在执行目标函数前附加一些内容或者功能：
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def demo(func): print('before exec %s '%func.__name__) func() print('after exec %s '%func.__name__) return funcdef func(): print('hello world')func = demo(func)func() |
2.使用语法糖@来装饰函数
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def demo(func): print('before exec %s '%func.__name__) func() print('after exec %s '%func.__name__) return func@demodef func(): print('hello world')func() |
3.使用内嵌包装饰函数保证每次新函数都被调用
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def demo(func): def inner(): print('before exec %s '%func.__name__) func() print('after exec %s '%func.__name__) return inner@demodef func(): print('hello world')func() |
4.对带参数的函数进行装饰
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def demo(func): def inner(a,b): print('before exec %s '%func.__name__) ret = func(a,b) print('after exec %s '%func.__name__) return ret return inner@demodef func(a,b): print('hello world') return a+bprint(func(1,2)) |
5.对参数数量不确定的函数进行装饰
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def demo(func): def inner(*args,**kwargs): print('before exec %s '%func.__name__) ret = func(*args,**kwargs) print('after exec %s '%func.__name__) return ret return inner@demodef func(a,b): print('hello world func') return a+b@demodef func1(a,b,c): print('hello world func1') return a+b+cprint(func(1,2))print(func1(1,2,3)) |
6.装饰器带参数
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def demo(arg): def warper(func): def inner(*args,**kwargs): print('before exec %s %s'%(func.__name__,arg)) ret = func(*args,**kwargs) print('after exec %s %s '%(func.__name__,arg)) return ret return inner return warper@demo('qq')def func(a,b): print('hello world func') return a+b@demo('wechat')def func1(a,b,c): print('hello world func1') return a+b+cprint(func(1,2))print(func1(1,2,3)) |
7.多个装饰器装饰一个函数
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def wrapper1(func): def inner(): print('wrapper1 ,before func') func() print('wrapper1 ,after func') return innerdef wrapper2(func): def inner(): print('wrapper2 ,before func') func() print('wrapper2 ,after func') return inner@wrapper2@wrapper1def f(): print('in f')f() |
8.装饰器带类参数
9.装饰器带类参数，并分拆公共类到其他py文件中，同时演示了对一个函数应用多个装饰器
