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

[Mark H Harris]

On 4/6/14 12:31 PM, Rustom Mody wrote:

> I think python wins because it (usually) lets people do their thing
> (includes but not limited to CS-research)
> and gets out of the way.  To say therefore that it is irrelevant to the
> research is a strange inversion of its advantages.

    I think so too. I find python useful for modeling (prototyping) 
constructs that it [python interpreter] was not 'designed' to do.

> [Or simply just switch to C++ for 3 months and report back with
> the increment in your white-hair-count]

    Back in the day I used Rexx to prototype a new language idea, or a 
new computational technique. Today I use python for prototyping.

    From a CS standpoint I can use python for research in morphology 
because of the flexibility and extensibility of the namespace, and the 
easy ability to create new nouns and verbs through 'def' (as either 
function or generator) and the iterative process over data types like 
'list' and 'dict'. I am playing with neural nets again, using python, 
and liking the fact that I can put my ideas into practice easily and 
python gets out of the way. I find it a great research language. I am 
surprised that others only see it as a problem solving tool.


    I have another question for y'all, is a function (particularly a 
generator) a noun or a verb?  Does a function (or generator) 'do' 
something (based on name and parms) or does it 'return' something based 
on name and parms? Based on name and parms should a function (or 
generator) function as a noun, or function as a verb, or *both*? --or, 
are Classes nouns only, and all functions *are* verbs only?


marcus