Explanation of this Python language feature? [x for x in x for x in x] (to flatten a nested list)

[Marko Rauhamaa]

Mark H Harris <harrismh777 at gmail.com>:

> 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.

>From the point of view of computer science, those barely register. We
have had a revolution in hardware and software engineering, not computer
science.

> 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.

Yes, but not much has taken place since in computer science. Even
virtualization was well covered before WWII from the scientific point of
view.

> 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?

Little to write home about so far. Well, having Fritz beat the best
human chess players is impressive, to be sure. A testament to the power
of brute force. Similarly with Google and Big Data. But again, those are
not scientific advances.

> 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?

True, the mathematicians gave up on justifying their existence and went
back to counting beads. The foundational excitement still remains in
physics.

What does computer science have to show of late? A better mutual
exclusion algorithm? Dancing trees?

Ok, cryptography has been pretty exciting. The back and forth between
feasibility and unfeasibility. The ongoing cat and mouse.


Marko