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

[Chris Angelico]

On Sat, Apr 5, 2014 at 9:52 AM, Mark H Harris <harrismh777 at gmail.com> wrote:
> On 4/4/14 5:39 PM, Chris Angelico wrote:
>>
>> Yes, because python-list responses are *so* much more reliable than
>> official statements on python.org,
>
>
> {/sarcasm off}
>
> ... from some responders. The discussion following such posts is also *much*
> more valuable, too.  IMHO
>
> Python.org is the political place to start; but its not much good after
> that, in regards the forking of 2.7 --> 2.8

Official statements on python.org are the perfect place to find out
whether or not there'll be a 2.8. And that's exactly what PEP 404
details.

> As Ian points out, you can't expect a complete migration on the PSF schedule
> (2->3), because of the fear|panic  of a fork. So, comp.lang.python is the
> best place to find out where the Cpython community is, and where they expect
> to go (for that discussion).

What *is* the PSF schedule? Have you read that? Do you know when the
PSF expects all code to transition from Py2 to Py3? Because you can
find that on python.org too (at least some estimates).

> What I'm trying to say is that I tap many resources (comp.lang.python is
> just one of them) and I'm going to tap that source even though I also tap
> the Internet with a google search (and others).
>
> Eeyore doesn't like to be bugged, by double line spaces, nor by questions.
> What's the point of having a comp.lang.python news list if its not open for
> simple questions of opinion?  Yes, I know google is my friend.
> Comp.lang.python should be my friend too.

You're certainly free to ask. And we're free to tell you to use a
search engine to find authoritative responses :)

ChrisA