The "fluent interface" (https://en.wikipedia.org/wiki/Fluent_interface) is popular in many programming languages, including in the sort of "mini-language" Pandas, within portion.

But it is definitely not Pythonic. The Wikipedia article even shows how you *could* do it in Python, but mentions that Guido discourages it.

What we get instead is a clear divide between mutating methods on collections that (almost)  always return None, and functions like sorted() and reversed() that return copies of the underlying collection/iterable. Of course, there are many methods that don't have functions matching them. Python could have been designed differently, but using the consistency it follows is best.

On Sun, Jan 19, 2020, 1:17 PM Siddharth Prajosh <sprajosh@gmail.com> wrote:


On Sun, Jan 19, 2020 at 10:03 PM Guido van Rossum <guido@python.org> wrote:
I'm not excited about suggesting the walrus operator when people want to chain mutating method calls like this. It results in ugly code with way too many parentheses and a distinctly un-Pythonic flavor. I hope the OP doesn't go off and infect a whole subcommunity with this idiom.

Not a huge fan the walrus operator, yet. I don't think I'll use it unless necessary.

I'll stick to a = list() and then a.append() in this case


On Sat, Jan 18, 2020 at 10:05 PM Inada Naoki <songofacandy@gmail.com> wrote:
On Sun, Jan 19, 2020 at 2:45 PM Siddharth Prajosh <sprajosh@gmail.com> wrote:
>
> Moreover, shouldn't it work?
> How do I add that feature in Python?

How you can do it with warus operator.

>>> (xs := list(range(10))).append(42)
>>> xs
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 42]

Regards,

--
Inada Naoki  <songofacandy@gmail.com>
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-leave@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/24YMTGYKCNFHS2JROYSNSP6MUPZAFUCV/
Code of Conduct: http://python.org/psf/codeofconduct/


--
--Guido van Rossum (python.org/~guido)
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-leave@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/HEG7CAAG7KMFO2G6I4SOCG4QS7ZJTST2/
Code of Conduct: http://python.org/psf/codeofconduct/