【下载文档:  Python装饰器用法实例分析.txt 】

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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
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希望本文所述对大家Python程序设计有所帮助。