On Thu, May 17, 2018 at 1:03 AM, Ned Batchelder <n...@nedbatchelder.com> wrote: > On 5/16/18 10:06 AM, Steven D'Aprano wrote: >> >> On Wed, 16 May 2018 09:23:02 -0400, Ned Batchelder wrote: >> >>> I've also experimented with different ways to better say "everything is >>> an object". One possibility is, "any right-hand side of an assignment >>> is an object," though that is a bit tortured. >> >> What if there's no assignment? >> >>> Now I'm thinking of trying, "Any piece of data is an object." >> >> Is None data? How about True and False? >> >> Surely object() isn't data... and if it is, what about len? >> > This is what I meant by the complication when you get to a deeper discussion > of all the possible kinds of Python values. I think even beginners would > consider True and False as data. The others take more explanation. >
None takes only a little more explanation. It's data that says you have no data. It's like asking "is zero a number?" - yes, there's a mental leap to be made, but since it is so _exactly_ like zero's status, it's not too hard to explain. (Nothing like as bad as explaining SQL's NULL, which sometimes is a value, sometimes is a placeholder meaning "there is no value here", sometimes is a non-value, and sometimes just defies categorization.) Explaining that *len* is data requires the concept of "functions are things, too", which definitely takes some grokking. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
