[Tutor] Extending a list within a list comprehension

[Victor Bouffier]

On Tue, 2006-04-11 at 23:42 +0100, Alan Gauld wrote:
> Hi Victor,
> 
> I've gotta say that I much prefer the second version here.
> 
> > temporal = []
> > temporal = [ [x[1][1], (x[0], description[x[0]],
> >    x[1][0], x[1][1], x[1][2] ) ] for x in elements ]
> > temporal.sort()
> > temporal.reverse()          # sort descending
> > elements = [ x[1] for x in temporal ]
> > 
> > 
> > temporal = []
> > for x in elements:
> >    lst = [x[0], description[x[0]]]
> >    lst.extend(x[1])
> >    temporal.append([x[1][1], lst])
> > temporal.sort()
> > temporal.reverse()          # sort descending
> > elements = [ x[1] for x in temporal ]
> > 
> 
> That looks a lot easier to rtead (and debug) and will I suspect be 
> easier to maintain. Copmprehensions are great but unfortunately 
> can rapidly become incomprehensible!
> 
> > Is there a way to use list comprehensions to append or extend the array
> > as needed by the second code listing?
> 
> There may be but I wouldn't try.
> I might however look at using a simple list or dictionary of objects based 
> on a class... It might be easier.
> 
> Alan G
> 
> 

Hi Alan,

I believe you are right. The most pythonic way is not always the most
"perlish" way ;-) (no offense intended to Perl-comers, but Perl does
tend to promote nesting of expressions).

It is much easier to read and maintain, which is what I will need to do
eventually.
Thanks for the feedback.

Victor