Comparing sequences with range objects

[Peter J. Holzer]

On 2022-04-07 17:16:41 +0200, Antoon Pardon wrote:
> Op 7/04/2022 om 16:08 schreef Joel Goldstick:
> > On Thu, Apr 7, 2022 at 7:19 AM Antoon Pardon<antoon.pardon at vub.be>  wrote:
> > > I am working with a list of data from which I have to weed out duplicates.
> > > At the moment I keep for each entry a container with the other entries
> > > that are still possible duplicates.
[...]
> Sorry I wasn't clear. The data contains information about persons. But not
> all records need to be complete. So a person can occur multiple times in
> the list, while the records are all different because they are missing
> different bits.
> 
> So all records with the same firstname can be duplicates. But if I have
> a record in which the firstname is missing, it can at that point be
> a duplicate of all other records.

There are two problems. The first one is how do you establish identity.
The second is how do you ween out identical objects. In your first mail
you only asked about the second, but that's easy.

The first is really hard. Not only may information be missing, no single
single piece of information is unique or immutable. Two people may have
the same name (I know about several other "Peter Holzer"s), a single
person might change their name (when I was younger I went by my middle
name - how would you know that "Peter Holzer" and "Hansi Holzer" are the
same person?), they will move (= change their address), change jobs,
etc. Unless you have a unique immutable identifier that's enforced by
some authority (like a social security number[1]), I don't think there
is a chance to do that reliably in a program (although with enough data,
a heuristic may be good enough).

        hp

-- 
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | hjp at hjp.at         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"
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