Small correction: isinstance(x, int) should be x.isdigit() in the last
example.
On Fri, Apr 30, 2021 at 2:14 PM David Álvarez Lombardi <
alvarezd...@gmail.com> wrote:
> I appreciate the feedback, but I don't think the proposed ideas address
> any of my points.
>
> 1. *Consistency *(with other comprehensions)
> 2. *Intuitiveness *(as opposed to str.join(iter) which is widely
> deemed to be confusing and seemingly-backwards)
> 3. *Efficiency *(with respect to line count and function calls...
> though perhaps the cpython implementation could actually avoid the type
> switching and improve time complexity)
> 4. *Readability *(due to *much *clearer typing and lack of
> highly-nested function calls ( f"[{','.join('0123')}]" ) and
> higher-order functions ( genjoin('', '', '')('0123') )
>
> I would also like readers/commenters to consider the fact that, though I
> have only provided one use-case, the proposed enhancement would serve as
> the primary syntax for constructing or filtering a string *when dependent
> on any other iterable or condition*. I believe this to be an
> extremely common (almost universal) use-case. Here are just a couple more
> examples.
>
> new = c"x.lower() for x in old if x in HARDCODED_LIST" # filter-in chars
> that appear in earlier-defined HARDCODED_LIST and convert to lower
> new = c"x for x in old if not x.isprintable()" # filter-in
> non-printable chars
> new = c"str(int(x) + 1) for x in old if isinstance(x, int)" # increment
> all integers by 1
>
> To me, it is hard to see how any argument against this design (for
> anything other than implementation-difficulty or something along these
> lines) can be anything but an argument against iter comprehensions in
> general... but if someone disagrees, please say so.
>
> My goal is to *decrease* complexity, and personal/higher-order/nested
> procedures do not accomplish this in my eyes.
>
> Thank you.
>
> DQAL
>
> On Fri, Apr 30, 2021 at 1:10 PM Jonathan Fine <jfine2...@gmail.com> wrote:
>
>> On Fri, Apr 30, 2021 at 6:00 PM Chris Angelico <ros...@gmail.com> wrote:
>>
>> For those cases where you're merging literal parts and generated
>>> parts, it may be of value to use an f-string:
>>>
>>> >>> f"[{','.join('0123')}]"
>>> '[0,1,2,3]'
>>>
>>> The part in the braces is evaluated as Python code, and the rest is
>>> simple literals.
>>>
>>
>> For readability, reuse and testing I think it often helps to have a
>> function (whose name is meaningful). We can get this via
>> as_list_int_literal = gensep(',', '[', ']')
>>
>> It would also be nice to allow as_list_int_literal to have a docstring
>> (which could also be used for testing).
>>
>> I accept that in some cases Chris's ingenious construction has benefits.
>>
>> --
>> Jonathan
>>
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>
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