Explanation of list reference

[Chris Angelico]

On Sat, Feb 15, 2014 at 5:54 PM, Steven D'Aprano
<steve+comp.lang.python at pearwood.info> wrote:
> On Sat, 15 Feb 2014 15:37:20 +1100, Chris Angelico wrote:
>
> [...]
>> This is why dice exist in a variety of colors [1]. Indistinguishable yet
>> distinct dice...
>
> Since they have different colours, they can be distinguished and aren't
> indistinguishable.

Sorry, what I meant was that different colors are available for
purchase, as a means of avoiding this problem. If you buy a dozen dice
in mixed colors, you can simply declare "the red one is the hundreds,
the blue one is tens, the green one is units", which is the most
common solution to this exact issue of dice being indistinguishable
yet distinct.

> One might also distinguish three dice by position in space ("the die
> closest to the wall counts as the HUNDREDS digit, the one closest to me
> counts as the TENS digit, and the one closest to you counts as the UNITS
> digit")

Yes, but prior to rolling, you can't necessarily know what's going to
be easy to determine. Rolling dice tends to randomize their positions
somewhat, and it's impractical to get out the tape measure to
determine which one is closest to the wall :)

> or by space ("roll this die first for the HUNDREDS, then roll
> that one for TENS, then this third one for UNITS").

Distinguishing by time is the other common method that I mentioned. In
that case, there's really no reason to distinguish them at all, so you
can use the same object three times - like using the string "foobar"
three times and perhaps finding that it's the same object.

> Or scent, or texture, or the typeface used for the numbers.

Then they're not indistinguishable :)

Having grown up in a business that sells dice (though, oddly enough,
not for RPGs - I learned that d12s are popular for practicing
multiplication tables, not that they're used for a barbarian's hit
points and great-axe damage), I know how many identical dice you can
get hold of. We had trays and trays of them at one point... then
migrated to bulk bags. Though we usually tried to split them up, 50
dice per bag, so we could keep some track of inventory. And we were
retailing, and dice weren't a huge part of our business. There are
plenty of ways for dice to differ, but that's like having 5, 5.0, 5L
(if Py2), and (5+0j), all of which are five, but all of which are
distinct and must be kept separate.

ChrisA