[Python-ideas] Multi Statement Lambdas

[Marko Ristin-Kaufmann]

Hi,
What about writing longer map&reduces in pyspark? When I worked with Spark
and Scala, it was easy to script a longer chain of transformations in
Scala. Does anybody know how that works in Python without multiline lambdas?

Cheers Marko


Le dim. 21 oct. 2018 à 18:40, Ron Reiter <ron.reiter at gmail.com> a écrit :

> Multi-line lambdas may be nice for functional languages, but Python is
> very imperative in nature and prefers clean syntax over conciseness, which
> means it will make it REALLY hard to fit with Python. I personally find
> multi-line lambdas an unreadable abomination.
>
> As for some more concrete reasons on why this should not be a part of
> Python, see here for an example which shows why it would even be hard to
> come up with a plausible syntax for multi-line lambdas:
>
> https://stackoverflow.com/questions/1233448/no-multiline-lambda-in-python-why-not
>
> Guido's words:
>
> "But the complexity of any proposed solution for this puzzle is immense,
> to me: it requires the parser (or more precisely, the lexer) to be able to
> switch back and forth between indent-sensitive and indent-insensitive
> modes, keeping a stack of previous modes and indentation level. Technically
> that can all be solved (there's already a stack of indentation levels that
> could be generalized). But none of that takes away my gut feeling that it
> is all an elaborate Rube Goldberg contraption."
>
> If one would find a syntax which is Pythonic and clean then I am in favor
> of adding it, but I argue it simply does not exist.
>
> - Ron
>
>
> [image: Facebook] <http://www.facebook.com/ron.reiter> [image: Twitter]
> <http://twitter.com/#!/ronreiter> [image: LinkedIn]
> <https://il.linkedin.com/in/ronreiter>
>
>
> On Sun, Oct 21, 2018 at 7:34 PM Anders Hovmöller <boxed at killingar.net>
> wrote:
>
>>
>> Wheres a lambda expression can be passed anonymously to any other
>> function as an argument.
>>
>> *map(lambda x: x**2, array)*
>>
>> vs
>>
>> *def powers2(x)*
>> *   x**2*
>> *map(powers2, array)*
>>
>> Coming up with a name here is not needed, as the operation is expressive
>> enough.
>>
>>
>> Sure, but there is a well known convention for such non-names already:
>> meta syntactical variables. In this case the name could be "foo" and all
>> readers will interpret this as "no name".
>>
>> I admit to have wanted lambdas that are just as powerful as normal
>> functions, but often when I want it the code is nicer when a normal
>> function is used.
>>
>> / Anders
>> _______________________________________________
>> Python-ideas mailing list
>> Python-ideas at python.org
>> https://mail.python.org/mailman/listinfo/python-ideas
>> Code of Conduct: http://python.org/psf/codeofconduct/
>>
> _______________________________________________
> Python-ideas mailing list
> Python-ideas at python.org
> https://mail.python.org/mailman/listinfo/python-ideas
> Code of Conduct: http://python.org/psf/codeofconduct/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20181021/8b8de286/attachment-0001.html>