Explanation of this Python language feature? [x for x in x for x in x] (to flatten a nested list)
Mark H Harris
harrismh777 at gmail.com
Thu Apr 3 14:55:06 EDT 2014
On 4/3/14 12:14 PM, Marko Rauhamaa wrote:
> Mark H Harris <harrismh777 at gmail.com>:
>
>> So, python(3)'s use of unicode is exciting, not only as a step forward
>> for the python interpreter, but also as a leadership step forward in
>> computer science around the world.
>
> Big words. I don't think computer science has experienced major steps
> forward since the 1930's: combinatory logic, the Turing machine, the
> Entscheidungsproblem, the halting problem,...
>
> The one major latter-day addition is complexity theory (1960's).
hi Marko, computer science covers everything from a linked list to
virtual reality, from cpu pipe lining to flash memory, from punched tape
i/o to plasma displays--- to led back-lit flat panels. Computer science
also includes theory, and most of what you mention actually had its
beginnings in mathematics, not computer science. And yet, most of what
you mention as fundamental to computer science is only the beginning.
The Turning a-machines together (and parallel to) Alonzo Church's lambda
calculus (diverse methodologies on computability) brought a negative
answer on the Entscheidungsproblem; so much so that one might even think
that artificial intelligence were impossible. Alan Turning proved
(before computers ever existed) that one a-machine may not determine
whether another a-machine configuration will loop or halt. So what? Do
we cease to work towards artificial intelligence? Do you believe that
the AI work at MIT (using lisp) was a non step forwards for artificial
intelligence; for computer science?
Did not David Hilbert get a kick-in-the-pants? You might have thought
that mathematics at IAS would have folded its tents and blown away after
Kurt Gődel proved (mostly as consequence of self-reference) that if an
axiomatic system is complete it is also inconsistent, and if consistent
assuredly incomplete! There are true statements which cannot be proven!
Oh, crap. There must be systems of computation for which there is no
proof, yet function non-the-less. Does this impact computer science
today; does this impact AI studies today?
We as human beings have only just begun. The human mind is a quantum
computer. Can a bit be 1 and 0 at the same time?? It most certainly
can; entanglement is a computational reality that we have only just
begun to think about let alone comprehend, nor code for (whatever we
might mean by that).
Mathematicians hate this, but, computers are the way forward for
mathematics. Computer proofs are increasing; we are discovering that
proofs of import are requiring computers and computation algorithms. We
don't through our straight edges and compasses away; nor do we toss out
our BIC pens and paper. Algorithm is what is needed because the
mathematics is too complicated. Computer science is moving understanding
forward with algorithm.
Beyond all of that is communication. That is where unicode comes in.
Computer science is going to handle the problem of Universal
Translation. Great strides have been taken towards this already. More
are sure to come.
שלם
marcus
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