El jue, 21 oct 2021 a las 10:25, David Mertz, Ph.D. (<david.mertz@gmail.com>) escribió:
I've moved this to python-ideas where it is more appropriate, as Chris notes
On Thu, Oct 21, 2021, 8:42 PM Chris Angelico <rosuav@gmail.com> wrote:
On Fri, Oct 22, 2021 at 3:23 AM David Mertz, Ph.D. <david.mertz@gmail.com> wrote:
On Thu, Oct 21, 2021 at 2:52 AM Steven D'Aprano <steve@pearwood.info>
wrote:
On Tue, Oct 19, 2021 at 05:09:42PM -0700, Michael Selik wrote:
None and its ilk often conflate too many qualities. For example, is
it
missing because it doesn't exist, it never existed, or because we never received a value, despite knowing it must exist?
30+ years later, and we cannot easily, reliably or portably use NAN payloads. Most people don't care. If we offerred them a dozen or a thousand distinct sentinels for all the various kinds of missing data, how many people would use them and how many would just stick to plain old None?
In data science, I have been frustrated by the sparsity of ways of spelling "missing value."
Might be worth redirecting this to -ideas.
Besides the distinction Michael points out, and that Steven did in relation to NaNs with payloads, I encounter missingness of various other sorts as well. Crucially, an important kind of missing data is data where the value I received seems unreliable and I have decided to *impute* missingness rather than accept a value I believe is unreliable.
But there is also something akin to what Michael points out (maybe it's just an example). For example, "middle name" is something that some people simply do not have, other people choose not to provide on a survey, and others still we just don't know anything beyond "it's not there."
This feels like something you should express with an enum for all the different kinds of missing data:
class MissingReason(enum.Enum): no_middle_name = 1 not_provided = 2 unknown = 3 middle_name: str | MissingReason This gives you more structured and precise data than None-plus-string-tag and avoids breaking the ecosystem by changing the meaning and behavior of None.