[Python-ideas] Fwd: Fwd: Fwd: unpacking generalisations for list comprehension

[Sven R. Kunze]

On 17.10.2016 20:38, David Mertz wrote:
> Under my proposed "more flexible recursion levels" idea, it could even 
> be:
>
>   [f(x) for x in flatten(it, levels=3)]
>
> There would simply be NO WAY to get that out of the * comprehension 
> syntax at all.  But a decent flatten() function gets all the flexibility.

I see what you are trying to do here and I appreciate it. Just one 
thought from my practical experience: I haven't had a single usage for 
levels > 1. levels==1 is basically * which I have at least one example 
for. Maybe, that relates to the fact that we asked our devs to use names 
(as in attributes or dicts) instead of deeply nested list/tuple structures.

Do you think it would make sense to start a new thread just for the sake 
of readability?

>     Honestly, it goes beyond just being "wrong". The repeated refusal to
>     even acknowledge any equivalence between [...x... for x in [a, b, c]]
>     and [...a..., ...b..., ...c...] truly makes it difficult for me to
>     accept some people's _sincerity_.
>
>
> I am absolutely sincere in disliking and finding hard-to-teach this 
> novel use of * in comprehensions.

You are consistent at least. You don't teach * in list displays, no 
matter if regular lists or comprehensions. +1

>  P.S. It's very artificial to assume user are unable to use 'from 
> itertools import chain' to try to make chain() seem more cumbersome 
> than it is.

I am sorry but it is cumbersome.


Regards,
Sven
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