Python装饰器用法实例分析

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

运行结果：

before calling  hello
hello
end calling  hello

带参数的装饰器:

#coding=utf-8
def log(func):
 def wrapper(name):
   print 'before calling ',func.__name__
   func(name)
   print 'end calling ',func.__name__
 return wrapper
@log
def hello(name):
 print 'hello',name
@log
def hello2(name):
 print 'hello',name
if __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-8
def 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
@log
def hello(name,age):
 print 'hello',name,age
@log
def hello2(name):
 print 'hello',name
if __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-8
def 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
@log
def hello2(name):
 print 'hello',name
if __name__=='__main__':
 hello('haha',2)

运行输出：

INFO before calling  hello
INFO args ('haha', 2) kvargs {}
hello haha 2
INFO end calling  hello

希望本文所述对大家Python程序设计有所帮助。

来源：https://blog.csdn.net/YANG_Gang2017/article/details/78568411