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

[Rustom Mody]

On Saturday, April 5, 2014 11:27:08 AM UTC+5:30, Chris Angelico wrote:
> On Sat, Apr 5, 2014 at 4:29 PM, Ben Finney wrote:
> > Without actual data - which neither of us has on this matter - all of
> > these hypotheses are unfounded speculation. Let's not draw any
> > conclusions in the absence of evidence.
> 
> Not to mention that there's not a lot of difference between an
> unemployed professional coder and a serious hobbyist. :)

Since I started this distinction, I would like to clarify that I dont take it
too seriously.
My impressions:
1. The number of people who read (lurk (on GG!!)) is significantly higher than those who post. 3 times? 10 times? Dunno

2. And they fall into an in-between limbo region: ie students -- some formal, 
some informal -- who would like to become python 'professionals' but
dont see themselves as that right now

And in case you missed it, I was suggesting that the idea that python 2
support should be cavalierly dropped implied a completely hobbyist viewpoint.

Professionalism implies at bottom that a client is God even if
he is being an asshole.  Intel, Microsoft, IBM and any successful brick-n-mortar
corp of your choice, will be seen to follow this principle scrupulously
Of course you are free to prefer the '90%'
[Run your favorite search engine on "90 percent of startups..."

Of course that does not mean that I find the 'conservatism' of python's choices happy.
Here is a recent thread https://mail.python.org/pipermail/python-list/2014-February/667169.html
and its contained link http://bugs.python.org/issue2506
I am too far removed from the details to comment on the technical merit of it
However reading it suggests that decisions are being made on 
"conservatism is good, change is not" basis