conventions/requirements for 'is' vs '==', 'not vs '!=', etc

[castironpi]

On May 20, 11:49 am, s0s... at gmail.com wrote:
> On May 20, 9:04 am, castironpi <castiro... at gmail.com> wrote:
>
>
>
>
>
> > On May 20, 5:04 am, Duncan Booth <duncan.bo... at invalid.invalid> wrote:
>
> > > John Salerno <johnj... at NOSPAMgmail.com> wrote:
> > > >>>> a = 'this is longer'
> > > >>>> b = 'this is longer'
> > > >>>> a == b
> > > > True
> > > >>>> a is b
> > > > False
>
> > > > In the above example, Python has created only one string called
> > > > 'hello' and both x and y reference it. However, 'this is longer' is
> > > > two completely different objects.
>
> > > That is true when run interactively, but the behaviour changes again if you
> > > run it as a script:
>
> > > C:\Temp>type t.py
> > > a = 'this is longer'
> > > b = 'this is longer'
> > > print a is b
>
> > > C:\Temp>t
> > > True
>
> > > In short, two equal strings may or may not be identical and any code which
> > > makes assumptions based on observed behaviour is broken. If you want to be
> > > able to test identity on strings safely then use the 'intern()' builtin to
> > > get repeatable behaviour.
>
> > > --
> > > Duncan Boothhttp://kupuguy.blogspot.com
>
> > There is no such thing as real true equals.
>
> That's quite some dark deep philosophy. Fortunately, computers are not
> as complicated as real life. I would argue that, programatically,
> there *is* such thing as "real true equals". I would also argue that
> that view is most certainly not shared by everyone.- Hide quoted text -
>
> - Show quoted text -

Mean as it sounds, bits are pigeonholes: 5+V or 0.  As such, computers
are able to simulate numerical identity, but, don't forget, all your
inputs are discretized (pigeonholed).

Symbolic (mathematical) identity (equality) is defined as a reflexive,
symmetric, transitive relation, and partitions its domain into
equivalence classes (membership in which is binary).  Symbols are
outside of cause.

Ma: Symbolic identity is a mathematical relation
Mb: Symbols are acausal
m: Matter is causal
C: Symbolic identity is not defined on matter.

Further, conclude computers are symbolic only.  Now, what can a hoard
of people do with some symbols?

But, I defer on the practical sense.