Python装饰器用法实例分析

2019-11-25 13:29:24

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本文实例讲述了Python装饰器用法。分享给大家供大家参考，具体如下：

无参数的装饰器

#coding=utf-8def log(func):  def wrapper():    print 'before calling ',func.__name__    func()    print 'end calling ',func.__name__  return wrapper@logdef hello():  print 'hello'@logdef hello2(name):  print 'hello',nameif __name__=='__main__':  hello()

运行结果：

before calling hello
hello
end calling hello

带参数的装饰器:

#coding=utf-8def log(func):  def wrapper(name):    print 'before calling ',func.__name__    func(name)    print 'end calling ',func.__name__  return wrapper@logdef hello(name):  print 'hello',name@logdef hello2(name):  print 'hello',nameif __name__=='__main__':  hello('haha')

运行结果：

before calling hello
hello haha
end calling hello

多个参数的时候:

#coding=utf-8def log(func):  '''  *无名字的参数  **有名字的参数  :param func:  :return:  '''  def wrapper(*args,**kvargs):    print 'before calling ',func.__name__    print 'args',args,'kvargs',kvargs    func(*args,**kvargs)    print 'end calling ',func.__name__  return wrapper@logdef hello(name,age):  print 'hello',name,age@logdef hello2(name):  print 'hello',nameif __name__=='__main__':  hello('haha',2)  hello(name='hehe',age=3)

输出:

end calling hello
before calling hello
args () kvargs {'age': 3, 'name': 'hehe'}
hello hehe 3
end calling hello

装饰器里带参数的情况

本质就是嵌套函数

#coding=utf-8def log(level,*args,**kvargs):  def inner(func):    def wrapper(*args,**kvargs):      print level,'before calling ',func.__name__      print level,'args',args,'kvargs',kvargs      func(*args,**kvargs)      print level,'end calling ',func.__name__    return wrapper  return inner@log(level='INFO')def hello(name,age):  print 'hello',name,age@logdef hello2(name):  print 'hello',nameif __name__=='__main__':  hello('haha',2)

运行输出：