On 2016-02-22, Steven D'Aprano <st...@pearwood.info> wrote: > On Tue, 23 Feb 2016 05:48 am, Marko Rauhamaa wrote: >> Jon Ribbens <jon+use...@unequivocal.co.uk>: >>> I was under the impression that the point of UUIDs is that you can be >>> *so* confident that there won't be a collision that for all practical >>> purposes it's indistinguishable from being certain. >> >> Yes, if you generate a random 128-bit number, it will be unique -- > > If you generate a second random 128 bit number, you have a chance of 1 in > 2**128 of a collision. All you can say is that it will be *very probably* > unique. (I might even allow "almost certainly" unique.)
If you are not prepared to say that something with a 340282366920938463463374607431768211455 / 340282366920938463463374607431768211456 chance of being true is not "certainly true" then I'm not sure how you would not be too scared to ever leave the house. Or not leave the house. I mean, you're probably going to be hit by 10^25 meteorites, which sounds painful. > If you generate 2**128 + 1 such numbers, you are *guaranteed* to ... have expired due to the heat death of the universe. -- https://mail.python.org/mailman/listinfo/python-list
