xor operator

[avi.e.gross at gmail.com]

I was going to ask a dumb question. Has any other language you know of made
something available that does what is being asked for and included it in the
main program environment rather than an add-on?

A secondary mention here has been whether short-circuiting functions like
"any" and "all" have been augmented with something like "has_n" that
evaluates arguments till it has found n or perhaps n+1 of what it wants then
skips the rest. Does any language supply something like that? What would
such a function return and does it have an "any" or an "all" side?

It sounds like if I asked if a list of integers has at least n prime numbers
in "any" mode, it should ignore any that are not primes till it finds n
primes or fails and returns true or false. If in "all" mode, I assume it
would have to be the first n items without a failure.

Fine, but then someone may want to know WHERE you stopped or for you to
return the sublist of the ones that made the match, or even return
everything that was skipped so you can later process that. Consider a long
list of jurors you process to place a dozen that qualify on a jury and then
later you want to choose from among the rest for another jury.

Human minds can come up with an amazing number of ideas including for
"useful" functions or features but I find the vast majority would rarely be
used as nobody remembers it is available and some fairly simple method using
other functions can easily be cobbled together.

-----Original Message-----
From: Python-list <python-list-bounces+avi.e.gross=gmail.com at python.org> On
Behalf Of Grant Edwards via Python-list
Sent: Monday, November 13, 2023 8:19 PM
To: python-list at python.org
Subject: Re: xor operator

On 2023-11-14, Dom Grigonis via Python-list <python-list at python.org> wrote:
>
>> Except the 'any' and 'all' builtins are _exactly_ the same as bitwise
>> or and and applided to many bits. To do something "in line" with that
>> using the 'xor' operator would return True for an odd number of True
>> values and False for an even Number of True values.
>
> Fair point.
>
> Have you ever encountered the need for xor for many bits (the one
> that I am NOT referring to)? Would be interested in what sort of
> case it could be useful.

Yes, it's used all the time in low-level communications protocols,
where it's often implemented in hardware. But, it is also not at all
unusual to implement it in software.

It's also not that unusual for the "count-ones" part of the function
you're asking for to be implemented in hardware by a CPU having an
instruction that counts the number of 1 bits in a register.

GCC has a low-level builtins called __builtin_popcount() and
__builtin-popcountl() that counts the number of 1's in an unsigned
(long) int.


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