Python装饰器的执行过程实例分析

#!/usr/bin/python
#coding: utf-8
# 装饰器其实就是对闭包的使用
def dec(fun):
 print("call dec")
 def in_dec():
 print("call in_dec")
 fun()
 # 必须加上返回语句，不然的话会默认返回None
 return in_dec
@dec
def fun():
 print("call fun")
# 注意上面的返回语句加上还有不加上的时候这一句执行的区别
print(type(fun))
fun()
'''
通过观察

#!/usr/bin/python
#coding: utf-8
import time, functools
def performance(unit):
 print("call performance")
 def log_decrator(f):
 print("call log_decrator")
 @functools.wraps(f)
 def wrapper(*arg, **kw):
 print("call wrapper")
 t1 = time.time()
 t = f(*arg, **kw)
 t2 = time.time()
 tt = (t2 - t1) * 1000 if unit == "ms" else (t2 - t1)
 print 'call %s() in %f %s' % (f.__name__, tt, unit)
 return t
 return wrapper
 return log_decrator
@performance("ms")
def factorial(n):
 print("call factorial")
 return reduce(lambda x, y: x * y, range(1, 1 + n))
print(type(factorial))
#print(factorial.__name__)
print(factorial(10))
'''接下来的是