// 請給 @performace 增加一個引數，允許傳入's'或'ms'：
@performance('ms')
def factorial(n):
    return reduce(lambda x,y: x*y, range(1, n+1))

import time

def performance(unit):
    def a(f):
        def b(*args, **kw):
            t1 = time.time()
            fn = f(*args, **kw)
            t2 = time.time()
            t = (t2-t1) if
 
 unit == 's' else (t2-t1)*1000
            print 'call %s() in %s %s' % (f.__name__, t, unit)
            return fn
        return b
    return a

@performance('ms')
def factorial(n):
    return reduce(lambda x,y: x*y, range(1, n+1))

print factorial(10)

• time.time() 獲取當前時間
• t = (t2-t1) if unit == ‘s’ else (t2-t1)*1000
  
  類似 js的三目運算 var t = unit == ‘s’ ? (t2-t1) : (t2-t1)*1000
• fn.__name__ 獲取函式名
• ‘call %s() in %s %s’ % (f._name_, t, unit) %加字母，可對字串傳參