On Mon, 14 Nov 2011 17:00:38 -0800, Russell E. Owen wrote: > Oops, I stripped so much out of my example that I stripped the ugly bit. > This is closer to the original and demonstrated the issue: > > def timeMethod(func): > name = func.__name__ + "Duration" > def wrapper(self, *args, **keyArgs): > t1 = time.time() > res = func(self, *args, **keyArgs) > duration = time.time() - t1 > self.timings[name] = duration > return res > return wrapper > > I don't like the way name is passed into wrapper. It works, but it looks > like magic. A class offers an obvious place to save the information. Or > I could just generate the name each time.
The pattern you are seeing is called a closure, and it is a very important, if advanced, part of Python programming. Of course, you don't *have* to use closures, but it isn't scarily-advanced (like metaclass programming) but only moderately advanced, and there will be a lot of code out there using closures. http://en.wikipedia.org/wiki/Closure_(computer_science) Basically a closure is a function which remembers just enough of its current environment (the value of non-local variables) so that it can continue to work in the future, even if those non-locals change or disappear. I take it you are aware that timing code as shown is only suitable for long-running code, and not small snippets? For small snippets, you should use the timeit module. You might also find this recipe useful: http://code.activestate.com/recipes/577896/ -- Steven -- http://mail.python.org/mailman/listinfo/python-list
