On Wed, Mar 4, 2020 at 10:22 AM Richard Damon <rich...@damon-family.org> wrote:
> > But on one narrow point, I'm trying to think of everything in the > standard library or builtins that actually forms a total order with > elements of the same type. > > * Not floats > > * I think not strings with unicode canonical equivalence, decomposition, > and normalization > > * Definitely not sets, tuples, lists, dicts, etc. > > * Arguably not Decimal because it is sensitive to decimal context > > * Complex clearly not > > * I think not datetimes under timezone issues (although any ordering is > certainly *wrong* given the vagaries of timezones) > > * Queues, deques, etc. don't even try, nor should they > > * Do array.array's lack even a partial order? > > So really I think we are left with wanting a test for whether something > is "int or Fraction". > > I think strings do have the Total Order property, because string equality > & etc does NOT get into the issues of Unicode canonical equivalence, I.e. > the equality test is that they are the same sequence of code points, > ignoring that multiple sequences of code points might be represent the same > same canonical character, in part because there isn’t a single definition > of that, as there is NFD/NFC and NFKD/NFKC equivalences which are different. > Fair enough. I'm kinda conflating (kinda deliberately) the Python level of "what does the less-than operator do" with "what is meaningfully less that what for the actual problem?" And I'm also fudging the Decimal question too. The relationship between *expressions* can vary by decimal context. But not of a value named by a single variable. However, the expression can be quite simple: >>> with decimal.localcontext() as ctx: ... ctx.prec = 2 ... print(+a < b) True >>> with decimal.localcontext() as ctx: ... ctx.prec = 10 ... print(+a < b) False -- Keeping medicines from the bloodstreams of the sick; food from the bellies of the hungry; books from the hands of the uneducated; technology from the underdeveloped; and putting advocates of freedom in prisons. Intellectual property is to the 21st century what the slave trade was to the 16th.
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