assert versus print [was Re: The curious behavior of integer objects]
rrr at ronadam.com
Tue Jan 16 06:27:40 CET 2007
Steven D'Aprano wrote:
> On Mon, 15 Jan 2007 21:01:35 -0600, Ron Adam wrote:
>> There have been times where I would like assert to be a little more assertive
>> than it is. :-)
>> ie.. not being able to turn them off with the -0/-00 switches, and having them
>> generate a more verbose traceback.
> If you want something more verbose, you have it:
>>>> assert False, "verbose traceback"
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> AssertionError: verbose traceback
> If you want something that won't be turned off by -O, you maybe need to
> write your own:
> def assert_(condition, msg=""):
> if not condition:
> raise AssertionError(msg)
>> Maybe have an alternative 'warn' as an alternative debugging version that could
>> be set to ignore, soft (print to log), and hard (raise an error).
> Check out the warnings module.
Yes, I know it's there. It just seems like assert and warn() overlap currently.
Assert doesn't quite fill warn()'s shoes, and warn() isn't as unassertive as
assert when it's turned off.
A warn statement could be completely ignored and not even cost a function call
when it's turned off like assert does now. I don't think it does that
currently. Isn't there always some overhead when using the warn() function. Or
is there some magic there?
An if-raise is just as fast as assert when evaluating as True, so there's no
speed advantage there unless you have a large percentage of raises. But it does
looks a lot nicer when you want a short positive test, verses a longer negative
test with a raise stuck on it.
But I think the developers would not consider this to be a big enough matter to
be worth changing. So I'll continue to ignore warn(), and also continue to be
un-assertive in my python code.
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