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

[Mark H Harris]

On 3/27/14 11:10 AM, Chris Angelico wrote:
> On Fri, Mar 28, 2014 at 2:44 AM, Mark H Harris <harrismh777 at gmail.com> wrote:
>> My comments here are not in the least hasty, nor are they generalizations.
>> They are based on long years of experience with "normal" users, {snip}


> Who is a "normal user"?

For the purposes of this list, a "normal" user is a reasonably 
intelligent college educated non "computer professional" non "computer 
scientist" non "expert" who for the moment has an interest in leveraging 
computer science and|or programming to solve everyday or other 
scientific problems (without) having to first become a computer 
professional, computer scientist, or expert.

Yes, there are many many of them. There are hundreds of millions of them 
in the world today.  There are only a handful of "experts" world-wide.

This "normal" set excludes power users, expert users, special purpose 
users and computer scientists. The "normal" users are those folks who 
want to get real answers to real problems *without* having to spend eons 
of time learning how to use the system. Enter python, SimplyPy, short 
tutorial (and on-line python docs) and whalla.

Now for Immanuel Kant (perception is reality); what do "normal" users 
expect?  Its the ten-million €uro question.

marcus