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

[Mark H Harris]

On 4/4/14 11:40 PM, Chris Angelico wrote:
> If it's too much work to make the changes to move something from
> Python 2.7 to Python 3.3, it's *definitely* too much work to rewrite
> it in a different language.

    Totally, no doubt.

> There would have to be some strong other
> reason for shifting, especially since there's a 2to3 but not a
> PytoRuby. And forking is a pretty huge job; someone's gotta maintain
> it.

    I agree there, too. That's why I don't think anyone should worry 
about a new program, nor about a fork. Nobody really wants to fork a 
programming language, esp one like python. It takes an entire team of 
dedicated people to support it--- jut not worth trying to do that.

> What's more likely is that, once python.org stops maintaining
> Python 2.x at all, people will just stay on 2.7.9 or {snip}
 > After that, it'll be like running old versions of
> anything else: you weigh the cost of migrating to the new version
> against the risk of exploits if you don't move. It's that simple.

    Yup, totally agree.  So, just do it.  Probably after 3.4 will be the 
right time. Beats me.


marcus