求帮助??装饰器问题
例子如下:
'''
Created on 2011-12-9
@author: Administrator
'''
'''
02 Created on 2011-3-23
03
04 @author: Administrator
05 '''
from time import time
def logged (when):
def log(f, *args, **kargs):
print('''called:
function: %s
args :%r
kargs:%r''' % (f, args, kargs))
def pre_logged(f):
def wrapper(*args, **kargs):
log(f, *args, **kargs)
print('in pre_logged')
return f(*args, **kargs)
return wrapper
def post_logged(f):
def wrapper(*args, **kargs):
print('in post_logged *')
now = time()
try:
return f(*args, **kargs)
finally:
log(f, *args, **kargs)
print('time delta: %s' % (time() - now))
print('in post_logged')
return wrapper
try:
return {"pre":pre_logged, "post":post_logged}[when]
except KeyError as e:
raise ValueError(e)('must be "pre" or "post" ')
@logged('pre')
@logged('post')
def hello(name):
print('hello, ', name)
hello('world!')
请问一下这个代码的执行过程是怎么样的??
它是怎么会去调用pre_logged和post_logged函数的????
[解决办法]
前面说的像嵌套函数调用可能说得不太对,你自己google几篇文件再理解一下吧。
又重新看了下代码和文章,并运行了几次,好像理解点了:
@logged('pre')@logged('post')def hello(name): print('hello, ', name)hello('world!')