[Python-ideas] Re: List - append

Well, mypy is often used primarily as a linter on steroids. Anyway, agreed with your point! On Tue, Jan 21, 2020 at 10:22 AM Andrew Barnert wrote: > On Jan 19, 2020, at 20:54, Guido van Rossum wrote: > > > > Actually, `bar = foo` is more likely to be detected by mypy, since it is > probably a

[Python-ideas] Re: List - append

On Jan 19, 2020, at 20:54, Guido van Rossum wrote: > > Actually, `bar = foo` is more likely to be detected by mypy, since it is > probably a type error (unless bar isn't used or is only used in an `Any` > context). For mypy, flagging bare `foo` is harder, because we would have to > introduce

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 04:27:30PM -0500, David Mertz wrote: > I'm not sure what you intend here: > > A fluent interface is normally implemented by using method chaining Indeed. *Implemented by*, not "the same as". > to implement method >

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 8:16 PM Andrew Barnert wrote: > On Jan 19, 2020, at 15:20, Guido van Rossum wrote: > > > On Sun, Jan 19, 2020 at 3:10 PM Tim Peters wrote: > >> [Guido, on Pythons before 1.0.2 always printing non-None expression >> statement results] >> > Heh. That was such a

[Python-ideas] Re: List - append

On Jan 19, 2020, at 15:20, Guido van Rossum wrote: > >> On Sun, Jan 19, 2020 at 3:10 PM Tim Peters wrote: >> [Guido, on Pythons before 1.0.2 always printing non-None expression >> statement results] >> > Heh. That was such a misfeature that I had thoroughly suppressed any >> > memory of its

[Python-ideas] Re: List - append

By the way, if anyone is actually interested in this other than for nostalgia , there have been a number of lengthy discussion on this list about "Fluent" interfaces for Python. LIke this one for instance:

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 11:59 AM Tim Peters wrote: > For a bit of history that I may have made up (heh - memory fades over > time!), as I recall, the very first Python pre-releases echoed to > stdout every non-None statement result. which is what MATLAB does, if you don't put a semi-colon at

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 3:10 PM Tim Peters wrote: > [Guido, on Pythons before 1.0.2 always printing non-None expression > statement results] > > Heh. That was such a misfeature that I had thoroughly suppressed any > > memory of its existence. -k indeed. :-) > > I prefer to think of it as a bit

[Python-ideas] Re: List - append

[Guido, on Pythons before 1.0.2 always printing non-None expression statement results] > Heh. That was such a misfeature that I had thoroughly suppressed any > memory of its existence. -k indeed. :-) I prefer to think of it as a bit of genius :-) The natural desire to avoid mounds of useless

[Python-ideas] Re: List - append

Heh. That was such a misfeature that I had thoroughly suppressed any memory of its existence. -k indeed. :-) On Sun, Jan 19, 2020 at 1:33 PM Tim Peters wrote: > [Guido] > > Sounds like a hallucination or fabrication. > > Nope! Turns out my memory was right :-) > > > The behavior of `for i in

[Python-ideas] Re: List - append

I should really upgrade to 1.02! % python Python 1.0.1 (Jul 15 2016) Copyright 1991-1994 Stichting Mathematisch Centrum, Amsterdam >>> def f(): ... for i in range(5): i ... >>> f() 0 1 2 3 4 On Sun, Jan 19, 2020 at 4:33 PM Tim Peters wrote: > [Guido] > > Sounds like a hallucination or

[Python-ideas] Re: List - append

[Guido] > Sounds like a hallucination or fabrication. Nope! Turns out my memory was right :-) > The behavior of `for i in range(10): i` in the REPL exists > to this day, and list.append() never returned a value. Sure, but those weren't the claims. The claim was that the result of an

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 3:56 PM Steven D'Aprano wrote: > > 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. > > I can't speak about Pandas, but what the OP

[Python-ideas] Re: List - append

On Jan 19, 2020, at 12:15, David Mertz wrote: > > In contrast, in pure Python, most of that you do is in loops over the > elements of collections. In that case is does a good job of drawing your eye > to the fact that a method is called but not assigned to anything. When I see >

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 02:37:14PM -0500, David Mertz wrote: > 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. I can't speak about Pandas, but what the OP is

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 08:32:43AM -0800, Guido van Rossum 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 >

[Python-ideas] Re: List - append

Sounds like a hallucination or fabrication. The behavior of `for i in range(10): i` in the REPL exists to this day, and list.append() never returned a value. The only thing I'm only 90% sure of is whether the REPL always ignored None values. On Sun, Jan 19, 2020 at 11:58 AM Tim Peters wrote: >

[Python-ideas] Re: List - append

[David Mertz ] > ... > 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

[Python-ideas] Re: List - append

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

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 10:03 PM Guido van Rossum 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

[Python-ideas] Re: List - append

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. On Sat, Jan 18,

[Python-ideas] Re: List - append

On Sun, 19 Jan, 2020, 11:35 Inada Naoki, wrote: > On Sun, Jan 19, 2020 at 2:45 PM Siddharth Prajosh > 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,

[Python-ideas] Re: List - append

On Sun, Jan 19, 2020 at 2:45 PM Siddharth Prajosh 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

[Python-ideas] Re: List - append

[M Siddharth Prajosh ] > This is more of a doubt than a new idea. Python has always worked > intuitively but this was a bummer. > > A list has an append method. So I can do list.append(value). > I tried doing list(range(10)).append(10) and it returns None. Yes. Most methods that mutate an object