Re: Formatting a str as a number

2024-08-27 Thread Grant Edwards via Python-list
On 2024-08-27, Gilmeh Serda via Python-list  wrote:
> On 25 Aug 2024 15:46:25 GMT, Stefan Ram wrote:
>
>> f"{int(number):>20,}"
>
> Great. Thanks. Do you have a link to where that's documented?
>
> I did web search, found nothing.

https://docs.python.org/3/library/string.html#formatspec
https://docs.python.org/3/reference/lexical_analysis.html#f-strings

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Re: python C-api and thread

2024-08-05 Thread Grant Edwards via Python-list
On 2024-08-05, aotto1968 via Python-list  wrote:

> Is it possible to run two completely independent Python interpreters
> in one process, each using a thread?
>
> By independent, I mean that no data is shared between the
> interpreters and thus the C API can be used without any other
> "lock/GIL" etc.

No, not using any OS I've ever seen. The usual definition of "threads"
is that they share data, and the definition of "processes" is that
processes don't share data.

How exactly does what you're trying to do differ from runnig two
Python interpreters in two processes?

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Re: Predicting an object over an pretrained model is not working

2024-07-31 Thread Grant Edwards via Python-list
On 2024-07-31, marc nicole via Python-list  wrote:

> I suppose the meaning of those numbers comes from this line
> predicts_dict[class_name].append([int(xmin), int(ymin), int(xmax),
> int(ymax), P[index]]) as well as the yolo inference call. But i was
> expecting zeros for all classes except smallball.

That's not how machine learning and object recognition works.

> Because the image only shows that,

You know that. The machine doesn't.

> and that a train and a sheep wont have any target position or any
> probability whatsoever in the image weirdobject.jpg

That depends on the training data and how the model works.

You should probably do some reading on neural networks, machine
learning, and pattern/object recognition. You appear to be trying to
use tools without understanding what they do or how they work.

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Re: Anonymous email users

2024-06-24 Thread Grant Edwards via Python-list
On 2024-06-24, Barry Scott via Python-list  wrote:
>> On 23 Jun 2024, at 06:58, Sebastian Wells via Python-list 
>>  wrote:
>> 
>> The spammers won the spam wars, so even if you have someone's real
>> e-mail address, that's no guarantee that you can contact them. [...]
>
> My email address is well known and yes I get spam emails.

I've been puzzled by this for a long time. Many people talk about how
they get so much spam e-mail that there's little chance they'll notice
if I send them an e-mail.

I've been using the same e-mail address for about 20 years. I've use
that e-mail address with probably close to 100 retailers, charities,
open-source projects, media sites, and various other organizations.

I get at most a few spam emails per week [I just checked my spam
folder: 8 in the past 30 days]. And Gmail is very, very close to 100%
accurate at filtering them out.  I can't remember the last time I
actually got a spam message in my inbox.

> A few years ago the spam count was greater than a 1,000 a month.

I'm baffled.  Is Gmail silently rejecting that much junk before it
even gets to the filter that puts stuff into my "spam" folder?

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Re: Anonymous email users

2024-06-18 Thread Grant Edwards via Python-list
On 2024-06-18, Mats Wichmann via Python-list  wrote:
> On 6/17/24 17:51, dn via Python-list wrote:
>
>> +1
>> 
>> The "public" part is not to embarrass posters, but recognition that 
>> there are likely other people 'out there' (or arriving in-future if they 
>> care to read the archives) experiencing a similar problem. (hence need 
>> for descriptive Subject lines - isn't the most difficult task in 
>> programming 'choosing names'?)
>
> well, one of two, along with cache invalidation and off-by-one errors 
> (according to the wags).
>
> I do agree with this, but mailman (2) archives aren't particularly 
> useful for searching, as they're organized in monthly chunks and you 
> have to keep clicking around - this list doesn't have a search engine as 
> it's not converted to be one of the mailman 3 lists.

Gmane used to have a usable search feature (along with a decent
threaded web UI to read the arhives), but that got lost during the
great gmane server/domain upheaval of 2016 (or whenever that was). I
still miss it.

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Re: Anonymous email users

2024-06-17 Thread Grant Edwards via Python-list
On 2024-06-17, Roel Schroeven via Python-list  wrote:

> FWIW, personally I (mostly) don't see the point of replying to people 
> personally. To me a public mailing list is much like any public forum, 
> where my expectation is that conversations happen in public. To me it 
> always feels weird when I get a personal reply when I make a public post 
> in a mailing list. I mostly ignore those, unless there's really 
> something in it that's best kept out of the public.

My sentiments exactly. I generally don't even read replies that get
mailed to me. They almost always seem to be copies of replies that
were also posted to the mailing list (which I read using an NNTP
client pointed at news.gmane.io).

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Re: From JoyceUlysses.txt -- words occurring exactly once

2024-06-08 Thread Grant Edwards via Python-list
On 2024-06-08, Larry Martell via Python-list  wrote:

> The original question struck me as homework or an interview question for a
> junior position. But having no clear requirements or specifications is good
> training for the real world where that is often the case. When you question
> that, you are told to just do something, and then you’re told it’s not what
> is wanted. That frustrates people but it’s often part of the process.
> People need to see something to help them know what they really want.

Too true.  You can spend all sorts of time getting people to pin down
and sign off on the initial requirements, but it all goes right out
the window when they get the first prototype.

  "This isn't what we want, we want it to do ."

  "It does what you specified."

  "But, this isn't what we want."

  ...

If you're on salary, it's all part of the job. If you're a contractor,
you either figure it in to the bid or charge for change orders.



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Re: From JoyceUlysses.txt -- words occurring exactly once

2024-06-05 Thread Grant Edwards via Python-list
On 2024-06-05, dn via Python-list  wrote:

> If you/your teacher can't define a "word", the code, any code, will 
> almost-certainly be wrong!

Back when I was a student...

When there was a homework/project assignemnt with a vague requirement
(and it wasn't practical to get the requirement refined), what always
worked for me was to put in the project report or program comments or
somewhere a statement that the requirement could be interpreted in
different ways and here is the precise interpretation of the
requirement that is being implemented.



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Re: From JoyceUlysses.txt -- words occurring exactly once

2024-06-04 Thread Grant Edwards via Python-list
On 2024-06-04, Edward Teach via Python-list  wrote:
> On Mon, 03 Jun 2024 14:58:26 -0400 (EDT)
> Grant Edwards  wrote:
>
>> On 2024-06-03, Edward Teach via Python-list 
>> wrote:
>> 
>> > The Gutenburg Project publishes "plain text".  That's another
>> > problem, because "plain text" means UTF-8and that means
>> > unicode...and that means running some sort of unicode-to-ascii
>> > conversion in order to get something like "words".  A couple of
>> > hoursa couple of hundred lines of Cproblem solved!  
>> 
>> I'm curious.  Why does it need to be converted frum Unicode to ASCII?
>> 
>> When you read it into Python, it gets converted right back to
>> Unicode...

> Well.when using the file linux.words as a useful master list of
> "words".linux.words is strict ASCII

I guess I missed the part of the problem description where it said to
use linux.words to decide what a word is. :)

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Re: From JoyceUlysses.txt -- words occurring exactly once

2024-06-03 Thread Grant Edwards via Python-list
On 2024-06-03, Edward Teach via Python-list  wrote:

> The Gutenburg Project publishes "plain text".  That's another
> problem, because "plain text" means UTF-8and that means
> unicode...and that means running some sort of unicode-to-ascii
> conversion in order to get something like "words".  A couple of
> hoursa couple of hundred lines of Cproblem solved!

I'm curious.  Why does it need to be converted frum Unicode to ASCII?

When you read it into Python, it gets converted right back to Unicode...



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Re: From JoyceUlysses.txt -- words occurring exactly once

2024-05-31 Thread Grant Edwards via Python-list
On 2024-05-31, Pieter van Oostrum via Python-list  
wrote:
> HenHanna  writes:
>
>> Given a text file of a novel (JoyceUlysses.txt) ...
>>
>> could someone give me a pretty fast (and simple) Python program that'd
>> give me a list of all words occurring exactly once?
>>
>>   -- Also, a list of words occurring once, twice or 3 times
>>
>> re: hyphenated words(you can treat it anyway you like)
>>
>>but ideally, i'd treat  [editor-in-chief]
>>[go-ahead]  [pen-knife]
>>[know-how]  [far-fetched] ...
>>as one unit.
>>
>
> That is a famous Unix task : (Sorry, no Python)
>
> grep -o '\w*' JoyceUlysses.txt | sort | uniq -c | sort -n

Yep, that's what came to my mind (though I couldn't remember the exact
grep option without looking it up).  However, I assume that doesn't
get you very many points on a homework assignemnt from an "Intruction
to Python" class.

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Re: Flubbed it in the second interation through the string: range error... HOW?

2024-05-29 Thread Grant Edwards via Python-list
On 2024-05-29, Mats Wichmann via Python-list  wrote:
> On 5/29/24 08:02, Grant Edwards via Python-list wrote:
>> On 2024-05-29, Chris Angelico via Python-list  wrote:
>> 
>>> print(f"if block {name[index]=} {index=}")
>> 
>> Holy cow!  How did I not know about the f-string {=} thing?
>
> It's more recent than f-strings in general, so it's not that hard to miss.

I really should make a habit of reading through the "what's new" pages
when new releases come out...

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Re: Flubbed it in the second interation through the string: range error... HOW?

2024-05-29 Thread Grant Edwards via Python-list
On 2024-05-29, Chris Angelico via Python-list  wrote:

> print(f"if block {name[index]=} {index=}")

Holy cow!  How did I not know about the f-string {=} thing?

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Re: Weird Stuff (Markdown, syntax highlighting and Python)

2024-05-27 Thread Grant Edwards via Python-list
On 2024-05-26, Gilmeh Serda via Python-list  wrote:
> The web claims (I think on all pages I've read about Markdown and Python) 
> that this code should work, with some very minor variants on the topic:
>
> ```python
>
> import os
>
> with open(os.path.join('/home/user/apath', 'somefile')) as f:
> print(f.read())
> ```
>
> However, that is not the case.

For me, that block formats as expected using Python markdown.

What do you mean by "this code should work [...] that is not the case"?

What markdown rendering engine are you using?

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Re: Terminal Emulator (Posting On Python-List Prohibited)

2024-05-19 Thread Grant Edwards via Python-list
On 2024-05-19, Barry via Python-list  wrote:
>
>
>> On 18 May 2024, at 16:27, Peter J. Holzer via Python-list 
>>  wrote:
>> 
>> I don't think Linux users have to deal with venvs
>
> Modern debian (ubuntu) and fedora block users installing using pip.

You can't even use pip to do "user" installs?

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Re: Terminal Emulator (Posting On Python-List Prohibited)

2024-05-19 Thread Grant Edwards via Python-list
On 2024-05-19, Gilmeh Serda via Python-list  wrote:
> On Sun, 19 May 2024 08:32:46 +0100, Alan Gauld wrote:
>
>> I've honestly never experienced this "nightmare".
>> I install stuff and it just works.
>
> Hear! Hear! Me too! And all that.
>
> I'm on Manjaro, which is a tad finicky about other people touching its 
> Python since it's used for lots of things. I install things for myself 
> only.
>
> Was there a reason they chose the name Pip?

I always assumed it was in honor of the PIP (Peripheral Interchange
Program?) utility that was used to copy files around on CP/M and DEC's
PDP-11 OSes.

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Re: Terminal Emulator (Posting On Python-List Prohibited)

2024-05-19 Thread Grant Edwards via Python-list
On 2024-05-19, Alan Gauld via Python-list  wrote:

>> The dependency nightmare created by python, pip
>> and all the rest cannot be resolved otherwise.
>
> I've honestly never experienced this "nightmare".
> I install stuff and it just works.

Same here.  I occasonlly use pip to install something that isn't
packaged for Gentoo, but it doesn't seem to cause problems — let alone
nightmares. I also occasionally package something myself.

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Re: Terminal Emulator (Posting On Python-List Prohibited)

2024-05-18 Thread Grant Edwards via Python-list
On 2024-05-18, Mats Wichmann via Python-list  wrote:

> Distros have do offer a good selection of packaged Python bits, yes, but 
> only for the version of Python that's "native" to that distro release. 
> If you need to test other versions of Python, you're mostly on your own.

For a few years I needed both 2.x and 3.x installed, but my distro
(Gentoo) handled that fine (I think most others do also). Gentoo also
allows multiple minor versions to be installed (currently I have 3.11
and 3.12 on this machine).

But, since Gentoo is a source-based meta-distro, when I install a
Python package, the package manager knows how to install it for all
installed Python versions that are supported by the package.

I can't think of why I would need a venv unless I needed to test
something with a Python version that isn't available for Gentoo. That
said, there are currently 7 versions available (2.7.18, 3.8.19,
3.9.19, 3.10.14, 3.11.9, 3.12.3, 3.13.0).

3.13 isn't marked stable yet in the Gentoo package database, and I
apparently have some Python app/package installed that doesn't yet
support 3.12, so I've currently got both 3.12 and 3.11.
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Re: Terminal Emulator (Posting On Python-List Prohibited)

2024-05-18 Thread Grant Edwards via Python-list
On 2024-05-18, Peter J. Holzer via Python-list  wrote:
> On 2024-05-16 19:46:07 +0100, Gordinator via Python-list wrote:
>
>> To be fair, the problem is the fact that they use Windows (but I
>> guess Linux users have to deal with venvs, so we're even.
>
> I don't think Linux users have to deal with venvs any more than
> Windows users. Maybe even less because many distributions come with
> a decent set of Python packages.

I've been using Python on Linux almost daily for 25 years, and I've
yet to use a venv...

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Re: Terminal Emulator

2024-05-14 Thread Grant Edwards via Python-list
On 2024-05-14, Alan Gauld via Python-list  wrote:
> On 14/05/2024 18:44, Gordinator via Python-list wrote:
>
>> I wish to write a terminal emulator in Python. I am a fairly
>> competent Python user, and I wish to try a new project idea. What
>> references can I use when writing my terminal emulator? I wish for
>> it to be a true terminal emulator as well, not just a Tk text
>> widget or something like that.
>
> The first thing is to decide which terminal.

If you want to make life easier, make it a superset of a terminal that
already exists in the terminfo database.

Going with some sort of ANSI terminal will probably provide
operability even with dumb apps which ignore $TERM and just spit out
basic ANSI escape sequences.

If you really want to break trail, you could invent your own control
sequences, which means you'll have to write terminfo and/or termcap
entries as well as the terminal emulator.

> A VT100 is very different from a 3270. And even a VT330 is quite
> different from a VT100 although sharing a common subset of control
> codes. And if you start looking at graphical terminals things get
> even more interesting!

"Intersting" is putting it mildly...





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Re: Terminal Emulator

2024-05-14 Thread Grant Edwards via Python-list
On 2024-05-14, Alan Gauld via Python-list  wrote:
> On 14/05/2024 18:44, Gordinator via Python-list wrote:
>
>> I wish to write a terminal emulator in Python. I am a fairly
>> competent Python user, and I wish to try a new project idea. What
>> references can I use when writing my terminal emulator? I wish for
>> it to be a true terminal emulator as well, not just a Tk text
>> widget or something like that.
>
> The first thing is to decide which terminal.

You also need to decide if you're going to support real serial ports
or just ptys.

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Re: How to Add ANSI Color to User Response

2024-04-10 Thread Grant Edwards via Python-list
On 2024-04-10, Alan Gauld via Python-list  wrote:
> On 10/04/2024 19:50, WordWeaver Evangelist via Python-list wrote:
>
>> I have a simple question. I use the following textPrompt in some of my 
>> Jython modules:
>>  '\nYour choice is? (A B C D E): ', maxChars=1, autoAccept=False, 
>> forceUppercase=True)
>> Is there a way to add an ANSI color code to the end
>
> Normally, for any kind of fancy terminal work, I'd say use curses.

If you want to use the terminal escape sequences provided by terminfo
and ncurses, but don't want to use the ncurses windowing functions,
here are some notes on how to do that:

https://github.com/GrantEdwards/Python-curses-and-terminfo

That too is C-Python oriented, and I don't really know how to do the
same things using Jython.

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Re: How to Add ANSI Color to User Response

2024-04-10 Thread Grant Edwards via Python-list
On 2024-04-10, WordWeaver Evangelist via Python-list  
wrote:

> I have a simple question. I use the following textPrompt in some of my Jython 
> modules:
>  '\nYour choice is? (A B C D E): ', maxChars=1, autoAccept=False, 
> forceUppercase=True)

> Is there a way to add an ANSI color code to the end where the
> conditions are, so that the color of the user’s input is of a color
> of my choosing, instead of just white?

I'm not sure what is meant by "the end where the conditions are", nor
do I know what "textPrompt" refers to.

Are you asking how to put a second escape sequence at the end of the
string literal after the colon?

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Re: Popping key causes dict derived from object to revert to object

2024-03-25 Thread Grant Edwards via Python-list
On 2024-03-25, Loris Bennett via Python-list  wrote:
> Grant Edwards  writes:
>
>> On 2024-03-22, Loris Bennett via Python-list  wrote:
>>
>>> Yes, I was mistakenly thinking that the popping the element would
>>> leave me with the dict minus the popped key-value pair.
>>
>> It does.
>
> Indeed, but I was thinking in the context of 
>
>   dict_list = [d.pop('a') for d in dict_list]
>
> and incorrectly expecting to get a list of 'd' without key 'a', instead
> of a list of the 'd['a]'.

So when you say "leave me with", you mean "return the same dictionary
with"?  There's an important difference between what a function
returns and what global/local state it "leaves you with".

> Thanks for pointing out 'del'.  My main problem, however, was
> failing to realise that the list comprehension is populated by the
> return value of the 'pop', not the popped dict.

OK, so perhaps you weren't execting the original dict objects to be
mutated, but rather that the pop method would return a new dict object
without the "popped" element. The whole point of the 'pop method is to
return the popped value, otherwise it wouldn't be needed. The 'del'
statement would suffice.

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Re: Popping key causes dict derived from object to revert to object

2024-03-22 Thread Grant Edwards via Python-list
On 2024-03-22, Loris Bennett via Python-list  wrote:

> Yes, I was mistakenly thinking that the popping the element would
> leave me with the dict minus the popped key-value pair.

It does.

> Seem like there is no such function.

Yes, there is. You can do that with either pop or del:

>>> d = {'a':1, 'b':2, 'c':3}
>>> d
{'a': 1, 'b': 2, 'c': 3}
>>> d.pop('b')
2
>>> d
{'a': 1, 'c': 3}


>>> d = {'a':1, 'b':2, 'c':3}
>>> del d['b']
>>> d
{'a': 1, 'c': 3}

In both cases, you're left with the dict minus the key/value pair.

In the first case, the deleted value printed by the REPL because it
was returned by the expression "d.pop('b')" (a method call).

In the second case is no value shown by the REPL because "del d['b']"
is a statement not an expression.




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Re: the name ``wheel''

2024-03-21 Thread Grant Edwards via Python-list
On 2024-03-21, MRAB via Python-list  wrote:

> As it's recommended to use the Python Launcher py on Windows, I use
> that instead:
>
> py -m pip install something
>
> because it gives better support if you have multiple versions of
> Python installed.

I adopted that practice years ago on Linux as well after wasting what
seemed like most of a day trying to figure out problems which turned
out to be caused by the fact that "pip" and "python" invoked different
versions of Python.
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Re: Configuring an object via a dictionary

2024-03-15 Thread Grant Edwards via Python-list
On 2024-03-15, Thomas Passin via Python-list  wrote:
> On 3/15/2024 5:30 AM, Loris Bennett via Python-list wrote:
>> Hi,
>> 
>> I am initialising an object via the following:
>> 
>>  def __init__(self, config):
>> 
>>  self.connection = None
>> 
>>  self.source_name = config['source_name']
>>  self.server_host = config['server_host']
>>  self.server_port = config['server_port']
>>  self.user_base = config['user_base']
>>  self.user_identifier = config['user_identifier']
>>  self.group_base = config['group_base']
>>  self.group_identifier = config['group_identifier']
>>  self.owner_base = config['owner_base']
>> 
>> However, some entries in the configuration might be missing.  What is
>> the best way of dealing with this?
>> 
>> I could of course simply test each element of the dictionary before
>> trying to use.  I could also just write
>> 
>> self.config = config
>> 
>> but then addressing the elements will add more clutter to the code.
>> 
>> However, with a view to asking forgiveness rather than
>> permission, is there some simple way just to assign the dictionary
>> elements which do in fact exist to self-variables?
>> 
>> Or should I be doing this completely differently?
>
>  self.source_name = config.get('source_name', default_value)
>
> Or, if you like this kind of expression better,
>
>  self.source_name = config.get('source_name') or default_value

Won't the latter version misbehave if the value of config['source_name'] has a
"false" boolean value (e.g. "", 0, 0.0, None, [], (), {}, ...)

>>> config = {}
>>> config['source_name'] = ""
>>> config.get('source_name') or 'default'
'default'



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Re: pathlib.Path.is_file vs os.path.isfile difference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-08, Thomas Passin via Python-list  wrote:
>
>> Hi, I tested this with Python 3.8. Good to know that this was fixed!
>
> We just learned a few posts back that it might be specific to Linux; I 
> ran it on Windows.

On Linux, the limit is imposed by the filesystem.  Most of the "real"
filesystems on Linux have a 255 character limit, a few support 256,
and some of the legacy filesystems have lower limits. Reiser4 is the
only one that's even remotely common which supports more than 256 --
according to https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits
it supports filenames up to 3976 bytes long.

NB: The behavior when the limit is exceeded might also vary from one
filesystem to another.

In any case, the pathlib docs for is_file() are explicit: any errors
from the underlying OS and libraries will be propogated. There is
nothing to fix.

 https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_file

  Path.is_file()

Return True if the path points to a regular file (or a symbolic
link pointing to a regular file), False if it points to another
kind of file.

False is also returned if the path doesn’t exist or is a broken
symlink; other errors (such as permission errors) are propagated.
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Re: pathlib.Path.is_file vs os.path.isfile difference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-08, Grant Edwards via Python-list  wrote:

>> OSError: [Errno 36] File name too long: 
>> ''
>
> On all of the Linux filesystems I know about, the max length for a
> filename is 255 bytes, so the OSError is too surprising, and it does
> seem to follow the documentation.

Doh. I meant "is not too surprising".
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Re: pathlib.Path.is_file vs os.path.isfile difference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-08, Grant Edwards via Python-list  wrote:
> On 2024-03-08, Thomas Passin via Python-list  wrote:
>> On 3/8/2024 1:03 PM, Albert-Jan Roskam via Python-list wrote:
>>> Hi,
>>> I was replacing some os.path stuff with Pathlib and I discovered this:
>>> Path(256 * "x").is_file()  # OSError
>>> os.path.isfile(256 * "x")  # bool
>>> Is this intended? Does pathlib try to resemble os.path as closely as
>>> possible?
>>
>> You must have an very old version of Python.  I'm running 3.12.2 and it 
>> returns False.
>
> It throws OSError with Python 3.11.8 on Linux.

> OSError: [Errno 36] File name too long: 
> ''

On all of the Linux filesystems I know about, the max length for a
filename is 255 bytes, so the OSError is too surprising, and it does
seem to follow the documentation.

>>>> import os
>>>> os.path.isfile(256 * "x")
> False

However, os.path.isfile() apprently masks that error somehow and
returns False instead.

I notice that the os.path.isfile() documentation does not specify what
happens if the path is not a file or is illegal. It only specifies
that True is returned if the path is a regular file. Presumably
something other than "return True" is supposed to happen, but exactly
what is not specified.


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Re: pathlib.Path.is_file vs os.path.isfile difference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-08, Thomas Passin via Python-list  wrote:
> On 3/8/2024 1:03 PM, Albert-Jan Roskam via Python-list wrote:
>> Hi,
>> I was replacing some os.path stuff with Pathlib and I discovered this:
>> Path(256 * "x").is_file()  # OSError
>> os.path.isfile(256 * "x")  # bool
>> Is this intended? Does pathlib try to resemble os.path as closely as
>> possible?
>
> You must have an very old version of Python.  I'm running 3.12.2 and it 
> returns False.

It throws OSError with Python 3.11.8 on Linux.

$ python
Python 3.11.8 (main, Feb 23 2024, 16:11:29) [GCC 13.2.1 20240113] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pathlib
>>> pathlib.Path(256 * "x").is_file()
Traceback (most recent call last):
  File "", line 1, in 
  File "/usr/lib/python3.11/pathlib.py", line 1267, in is_file
return S_ISREG(self.stat().st_mode)
   ^^^
  File "/usr/lib/python3.11/pathlib.py", line 1013, in stat
return os.stat(self, follow_symlinks=follow_symlinks)
   ^^
OSError: [Errno 36] File name too long: 
''
>>>
>>> import os
>>> os.path.isfile(256 * "x")
False

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Re: Variable scope inside and outside functions - global statement being overridden by assignation unless preceded by reference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-08, Chris Angelico via Python-list  wrote:
> On Sat, 9 Mar 2024 at 00:51, Grant Edwards via Python-list
> wrote:
>
>> One might argue that "global" isn't a good choice for what to call the
>> scope in question, since it's not global. It's limited to that source
>> file. It doesn't make sense to me to call a binding "global", when
>> there can be multile different "global" bindings of the same name.
>
> Most "globals" aren't global either, since you can have different
> globals in different running applications.

To me, "global" has always been limited to within a single
process/address space, but that's probably just bias left over from
C/Pascal/FORTRAN/assembly/etc. It never occurred to me that a global
called "X" in one program on one computer would be the same as a
global called "X" in a different program on a different computer
somewhere else on the "globe".


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Re: Variable scope inside and outside functions - global statement being overridden by assignation unless preceded by reference

2024-03-08 Thread Grant Edwards via Python-list
On 2024-03-07, Cameron Simpson via Python-list  wrote:

> Yes. Note that the "global" namespace is the module in which the 
> function is defined.

One might argue that "global" isn't a good choice for what to call the
scope in question, since it's not global. It's limited to that source
file. It doesn't make sense to me to call a binding "global", when
there can be multile different "global" bindings of the same name.

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Re: Variable scope inside and outside functions - global statement being overridden by assignation unless preceded by reference

2024-03-06 Thread Grant Edwards via Python-list
On 2024-03-07, dn via Python-list  wrote:

> The idea of importing a module into the REPL and then (repeatedly) 
> manually entering the code to set-up and execute is unusual (surely type 
> such into a script (once), and run that (repeatedly). As you say, most 
> of us would be working from an IDE and hitting 'Run'. Am wondering why 
> you weren't - but it's not important.

Unless the code is intended to be used as a module, 'import'ing it into
the REPL doesn't make sense.

A simple example:

---testit.py--
x = 'x'
y = 'y'
def foo():
global y
print("hi")
x = 'X'
y = 'Y'
print(x)
print(y)
--

The usual method to play with that interactively is

$ python -i testit.py
>>> x
'x'
>>> y
'y'
>>> foo()
hi
X
Y
>>> x
'x'
>>> y
'Y'
>>>

As we've seen, doing a 'from testit.py import *' doesn't let you test
what the OP was trying to test. Doing 'import testit.py' gets you
closer, but it's a hassle to test code that way. The right thing to do
is 'python -i ' (or the equivalent button/option in an IDE).

  https://docs.python.org/3/tutorial/interpreter.html

If you intended to use testit.py as a module, and wanted to experiment
with its behavior as a module, then go ahead and import it. But, don't
do 'from testit.py import *' until

 1. you know how that differs from 'import testit.py'

and

 2. you want to use that difference


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Re: Variable scope inside and outside functions - global statement being overridden by assignation unless preceded by reference

2024-03-06 Thread Grant Edwards via Python-list
On 2024-03-06, Roel Schroeven via Python-list  wrote:
> Op 6/03/2024 om 17:40 schreef Jacob Kruger via Python-list:
>> >>> from scoping2 import *
>
> [...]
>
> I would advice not to use 'import *', if at all possible, for multiple 
> reasons, one of which is to prevent problems like this.

Unfortunately, many (most?) tutorials for particular modules (and even
example code in the Python documentation itself) are all written
assuming that you do "from  import *".  It saves the tutorial
write a few keystrokes, but causes untold trouble for people who learn
incorrectly that "from  import *" is the proper way to do
things.

> I would also advice not to use global variables from other modules
> directly, and in fact would advice to minimize the use of globals in
> general as much as possible. If you need to keep state between
> methods, it might be better to use a class.


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Re: Can u help me?

2024-03-06 Thread Grant Edwards via Python-list
On 2024-03-06, MRAB via Python-list  wrote:
> On 2024-03-06 01:44, Ethan Furman via Python-list wrote:
>> On 3/5/24 16:49, MRAB via Python-list wrote:
>>   > On 2024-03-06 00:24, Ethan Furman via Python-list wrote:
>>   >> On 3/5/24 16:06, Chano Fucks via Python-list wrote:
>>   >>
>>   >>> [image: image.png]
>>   >>
>>   >> The image is of MS-Windows with the python installation window of 
>> "Repair Successful".  Hopefully somebody better at
>>   >> explaining that problem can take it from here...
>>   >>
>>   > If the repair was successful, what's the problem?
>> 
>> I imagine the issue is trying get Python to run (as I recall, the python 
>> icon on the MS-Windows desktop is the
>> installer, not Python itself).
>
> There was an issue 3 years ago about renaming the installer for clarity:
>
> https://github.com/python/cpython/issues/87322

Yea, this problem comes up constantly (and has for many years).

People have suggested renaming the installer so it has "setup" or
"install" in the name.

People have suggested adding text to the installer splash screen to
explain that it's the installer and not python itself, that you
already have python installed, and if you want to _run_ python instead
of _install_ python, here's how.

People have suggested having the installer remove itself by default
when it's done installing.

People have suggested lots of solutions.

AFAICT, nobody has actually done anything.


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Re: Variable scope inside and outside functions - global statement being overridden by assignation unless preceded by reference

2024-03-05 Thread Grant Edwards via Python-list
On 2024-03-05, Cameron Simpson via Python-list  wrote:

> Because there are no variable definitions in Python, when you write
> a function Python does a static analysis of it to decide which
> variables are local and which are not. If there's an assignment to a
> variable, it is a local variable.  _Regardless_ of whether that
> assignment has been executed, or gets executed at all (eg in an
> if-statement branch which doesn't fire).

Unfortunately, crap "information" sites like geeksforgeeks often
describe this either incorrectly or so vaguely as to be worthless.
>From the page https://www.geeksforgeeks.org/global-local-variables-python/

 Python Global variables are those which are not defined inside
 any function and have a global scope whereas Python local
 variables are those which are defined inside a function and their
 scope is limited to that function only.

Since "define" (in this context) isn't a term of art in Python, and
it's never defined on the page in question, the quoted paragraph is
not meaningful: it simply says that "global variables are global and
local variables are local".

That page goes on to say:

 In other words, we can say that local variables are accessible
 only inside the function in which it was initialized

This is equally crap. It doesn't matter whether the variable is
initialized or not. As Cameron correctly stated, if a function
contains an assignment to a variable, and that variable is not
declared global, then that variable is local.  For example:

def foo():
print(s)
if 0:
s = "there"
print(s)

In the function above s _is_not_ initialized in the function foo().
However, foo() does contain an assignment to s, therefore s is local
unless declared global/nonlocal.  [And the first print() will throw an
exception even if there is a value bound to the global name 's'.]

Unfortunately (presumably thanks to SEO) the enshittification of
Google has reached the point where searching for info on things like
Python name scope, the first page of links are to worthless sites like
geeksforgeeks.

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Re: Problem resizing a window and button placement

2024-02-24 Thread Grant Edwards via Python-list
On 2024-02-24, MRAB via Python-list  wrote:
> On 2024-02-24 01:14, Steve GS via Python-list wrote:
>
>> Python, Tkinter: How do I determine if a window has been resized? I
>> want to locate buttons vertically along the right border and need
>> to know the new width. The buttons are to move with the change of
>> location of the right-side border.
>
> Bind an event handler for '':
>
> 8<
> [...]
> 8<
>
> Are you placing the buttons yourself? I always use layouts and they 
> handle such things automatically.

Yes, definitely what he said: use a layout manager.

I hope this doesn't sound rude, but if you're calculating button
positions based on window size, you're doing it wrong and will end up
wasting a lot of time to produce something that won't work right.

Use a layout manager:

  
https://tkinterpython.top/layout/#:~:text=Tkinter%20has%20three%20built%2Din,%2C%20grid%20%2C%20and%20place%20managers.

  
https://www.pythonguis.com/tutorials/create-ui-with-tkinter-pack-layout-manager/

  https://www.pythonguis.com/tutorials/use-tkinter-to-design-gui-layout/

You'll have to spend a little time learning how they work, but in the
end you'll get done sooner and have better results.

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Re: Can one output something other than 'nan' for not a number values?

2024-02-19 Thread Grant Edwards via Python-list
On 2024-02-19, Chris Green via Python-list  wrote:

> It's using f'{...}' at the moment.

Here's a demonstration of how to hook custom code into the f-string
formatting engine. It's brilliantly depraved.

https://stackoverflow.com/questions/55876683/hook-into-the-builtin-python-f-string-format-machinery

>From the above:

You can, but only if you write evil code that probably should
never end up in production software. So let's get started!

I'm not going to integrate it into your library, but I will show
you how to hook into the behavior of f-strings. This is roughly
how it'll work:

 1. Write a function that manipulates the bytecode instructions of
code objects to replace FORMAT_VALUE instructions with calls
to a hook function;

 2. Customize the import mechanism to make sure that the bytecode
of every module and package (except standard library modules
and site-packages) is modified with that function.

Final code is here:

https://github.com/mivdnber/formathack

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Re: Testing (sorry)

2024-02-19 Thread Grant Edwards via Python-list
On 2024-02-19, Thomas Passin  wrote:

>> About 24 hours later, all of my posts (and the confirmation e-mails)
>> all showed up in a burst at the same time on two different unrelated
>> e-mail accounts.
>> 
>> I still have no clue what was going on...
>
> Sometimes a post of mine will not show up for hours or even half a day. 
> They are all addressed directly to the list.  Sometimes my email 
> provider sends me a notice that the message bounced.  Those notices say 
> that the address wasn't available when the transmission was tried.

I guess that in future I'll wait a couple days before I assume
something is broken.

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Re: Testing (sorry)

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-18, Peter J. Holzer via Python-list  wrote:
> [Replying to the list *and* Grant]
>
> On 2024-02-17 19:38:04 -0500, Grant Edwards via Python-list wrote:
>> Today I noticed that nothing I've posted to python-list in past 3
>> weeks has shown up on the list.
>
> January 29th, AFAICS. And end of december before that.
>
>> I don't know how to troubleshoot this other than sending test
>> messages.  Obviously, if this shows up on the list, then I've gotten
>> it to work...
>
> This did show up and 3 other test messages with very similar text
> as well. 
>
> Also there was a whole flurry of almost but not quite identical messages
> from you in the "nan" thread.

Sorry about that.

All of those were posted at various times throughout the day yesterday
using two different accounts, two different mail servers, and three
different methods for submitting the e-mails.  I finally gave up and
switched to using comp.lang.python via Usenet.

Then, about 24 hours later, all those messages finally showed up.

At one point about half way through that process yesterday, I
unsusbscribed and then re-subscribed both e-mail addresses.  I got
confirmation and welcome messages on both accounts.  Sending "help"
requests to the list server produced the expected results. I enabled
the sending of confirmation messages from the list server.

But posts to the list still seemed to vanish into the ether while
emails from both accounts reached other destinations without delay,

During this process a number of posts from other users did appear in
the list archive and at at _one_ of the two e-mail addresses which I
had subscribed.

But no sign of any of my posts.

About 24 hours later, all of my posts (and the confirmation e-mails)
all showed up in a burst at the same time on two different unrelated
e-mail accounts.

I still have no clue what was going on...

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Testing (sorry)

2024-02-18 Thread Grant Edwards via Python-list
Today I noticed that nothing I've posted to python-list in the past 3
weeks has shown up on the list. I don't know how to troubleshoot this
other than by sending test messages.  Obviously, if this shows up on the
list, then I'm making progress...

[message 3]
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Testing (sorry)

2024-02-18 Thread Grant Edwards via Python-list



Today I noticed that nothing I've posted to python-list in past 3
weeks has shown up on the list. I don't know how to troubleshoot this
other than sending test messages.  Obviously, if this shows up on the
list, then I'm making progress.

[message 4]
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Testing - 2 (sorry)

2024-02-18 Thread Grant Edwards via Python-list
Today I noticed that nothing I've posted to python-list in past 3
weeks has shown up on the list. I don't know how to troubleshoot this
other than sending test messages.  Obviously, if this shows up on the
list, then I've gotten it to work...

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Testing (sorry)

2024-02-18 Thread Grant Edwards via Python-list
Today I noticed that nothing I've posted to python-list in past 3
weeks has shown up on the list. I don't know how to troubleshoot this
other than sending test messages.  Obviously, if this shows up on the
list, then I've gotten it to work...

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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-16, Chris Green  wrote:

> I'm looking for a simple way to make NaN values output as something
> like '-' or even just a space instead of the string 'nan'.

I tried monkey-patching the __format__ method of float, but it's
immutable, so that didnt' work.  Is float.__format__ what's used by
f-strings, the % operator, etc.?

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Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
[I've been trying all afternoon to post via slrn, but nothing is
showing up on the list.  Forgive me if multiple posts eventually show
up.]

On 2024-02-17, Cameron Simpson via Python-list  wrote:
> On 16Feb2024 22:12, Chris Green  wrote:
>>I'm looking for a simple way to make NaN values output as something
>>like '-' or even just a space instead of the string 'nan'.  [...]
>>
>>Battery Voltages and Currents
>>Leisure Battery - 12.42 volts  -0.52 Amps
>>Starter Battery - 12.34 volts  -0.01 Amps

> The simplest thing is probably just a function writing it how you
> want it:
>
>  def float_s(f):
>  if isnan(f):
>  return "-"
>  return str(f)

Since he's obviously using one of the float formatting mechanisms to
control the number of columsn and decimal places, I doubt str(f) will
meet the need.

I tried monkey-patching the float type's __format__ method, but it's
immutable.

Is float.__format__() what's used by f-strings, the '%' operator, etc.?

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Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
[Posts via slrn and my GMail account aren't showing up, so I guess I'll 
try

subscribing from a different e-mail address.]

On 2024-02-17, Cameron Simpson via Python-list  
wrote:

On 16Feb2024 22:12, Chris Green  wrote:

I'm looking for a simple way to make NaN values output as something
like '-' or even just a space instead of the string 'nan'.  [...]

   Battery Voltages and Currents
   Leisure Battery - 12.42 volts  -0.52 Amps
   Starter Battery - 12.34 volts  -0.01 Amps



The simplest thing is probably just a function writing it how you
want it:

 def float_s(f):
 if isnan(f):
 return "-"
 return str(f)


Since he's obviously using one of the float formatting mechanisms to
control the number of columsn and decimal places, I doubt str(f) will
meet the need.

I tried monkey-patching the float type's __format__ method, but it's
immutable.

Is float.__format__() what's used by f-strings, the '%' operator, etc.?


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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-17, Cameron Simpson via Python-list  wrote:
> On 16Feb2024 22:12, Chris Green  wrote:
>>I'm looking for a simple way to make NaN values output as something
>>like '-' or even just a space instead of the string 'nan'.  [...]
>>
>>Battery Voltages and Currents
>>Leisure Battery - 12.42 volts  -0.52 Amps
>>Starter Battery - 12.34 volts  -0.01 Amps

> The simplest thing is probably just a function writing it how you
> want it:
>
>  def float_s(f):
>  if isnan(f):
>  return "-"
>  return str(f)

Since he's obviously using one of the float formatting mechanisms to
control the number of columsn and decimal places, I doubt str(f) will
meet the need.

I tried monkey-patching the float type's __format__ method, but it's
immutable.

Is float.__format__() what's used by f-strings, the '%' operator, etc.?

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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-17, Cameron Simpson via Python-list  wrote:
> On 16Feb2024 22:12, Chris Green  wrote:
>>I'm looking for a simple way to make NaN values output as something
>>like '-' or even just a space instead of the string 'nan'.  [...]
>>
>>Battery Voltages and Currents
>>Leisure Battery - 12.42 volts  -0.52 Amps
>>Starter Battery - 12.34 volts  -0.01 Amps

> The simplest thing is probably just a function writing it how you
> want it:
>
>  def float_s(f):
>  if isnan(f):
>  return "-"
>  return str(f)

Since he's obviously using one of the float formatting mechanisms to
control the number of columsn and decimal places, I doubt str(f) will
meet the need.

I tried monkey-patching the float type's __format__ method, but it's
immutable.

Is float.__format__() what's used by f-strings, the '%' operator, etc.?

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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-17, Cameron Simpson via Python-list  wrote:
> On 16Feb2024 22:12, Chris Green  wrote:
>>I'm looking for a simple way to make NaN values output as something
>>like '-' or even just a space instead of the string 'nan'. [...]
>>
>>Battery Voltages and Currents
>>Leisure Battery - 12.42 volts  -0.52 Amps
>>Starter Battery -   nan voltsnan Amps
>>
>>What I would like is for those 'nan' strings to be just a '-' or
>>something similar.
>
> The simplest thing is probably just a function writing it how you want 
> it:
>
>  def float_s(f):
>  if isnan(f):
>  return "-"
>  return str(f)

He's obviouisly using a formatting feature to control columns and
decimal places, so I doubt that 'str(f)' is going to meet the need.

I tried monkey-patching the __format__ method of the 'float' type, but
it's immutable -- so that didn't work.

Is float.__format__() what's used by f-strings, the % operator, etc.?

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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-17, Cameron Simpson via Python-list  wrote:
> On 16Feb2024 22:12, Chris Green  wrote:
>>I'm looking for a simple way to make NaN values output as something
>>like '-' or even just a space instead of the string 'nan'.
>>[...]
>>
>>Battery Voltages and Currents
>>Leisure Battery - 12.42 volts  -0.52 Amps
>>Starter Battery -   nan voltsnan Amps
>>
>>What I would like is for those 'nan' strings to be just a '-' or
>>something similar.

> The simplest thing is probably just a function writing it how you want 
> it:
>
>  def float_s(f):
>  if isnan(f):
>  return "-"
>  return str(f)
>
> and then use eg:
>
>  print(f'value is {float_s(value)}')
>
> or whatever fits your code.

Except he's obviously using some sort of formatting to control the
number of columns and decimal places, so 'str(f)' is not going to cut
it. Is the basic floating point number formatting functionality seen
when using f-strings or '%' operator part of the float type or is it
part of the f-string and % operator?

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Re: Can one output something other than 'nan' for not a number values?

2024-02-18 Thread Grant Edwards via Python-list
On 2024-02-16, Chris Green via Python-list  wrote:

> I'm looking for a simple way to make NaN values output as something
> like '-' or even just a space instead of the string 'nan'.

It would probably help if you told us how you're "outputting" them now
(the Python feaatures/functions used, not the actual output format).

Are you using f-strings, the % operator, str.format(), or ??

I would be tempted to try monkey-patching the float class to override
the __format__ method. I have no idea what side effects that might
have, or if it's even used by the various formatting mechanisms, so
you might end up scraping bits off the walls...

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Re: Extract lines from file, add to new files

2024-01-29 Thread Grant Edwards via Python-list
On 2024-01-29, Rich Shepard via Python-list  wrote:
> On Mon, 29 Jan 2024, Rich Shepard via Python-list wrote:
>
>> No, I hadn't ... but I am reading it now.
>
> Perhaps I missed the answer to my question when reading the io module. It
> explains how to open/write/read files of text and binary data, not passing
> a variable's value from one file to a place-keeper in another file.

It's not at all clear (to me) what you're asking about.  When you talk
about "files" are you referring to data files? Python modules within a
single program? Seperate Python programs?  Something else?

The phrase "place-keeper in another file" sounds a bit like you're
trying to do templating. There are many, many ways to do templating in
Python -- ranging from literal 'f-strings' to powerful templating
engines that are used to construct entire web sites:

  https://www.google.com/search?q=python+templating

  https://docs.python.org/3/tutorial/inputoutput.html#tut-f-strings

  https://en.wikipedia.org/wiki/Jinja_(template_engine)

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Re: How/where to store calibration values - written by program A, read by program B

2023-12-29 Thread Grant Edwards via Python-list
On 2023-12-28, Peter J. Holzer via Python-list  wrote:
> On 2023-12-28 05:20:07 +, rbowman via Python-list wrote:
>> On Wed, 27 Dec 2023 03:53:42 -0600, Greg Walters wrote:
>> > The biggest caveat is that the shared variable MUST exist before it can
>> > be examined or used (not surprising).
>> 
>> There are a few other questions. Let's say config.py contains a variable 
>> like 'font' that is a user set preference or a calibration value 
>> calculated by A to keep with the thread title. Assuming both scripts are 
>> running, how does the change get propagated to B after it is set in A
>
> It isn't. The variable is set purely in memory. This is a mechanism to
> share a value between multiple modules used by the same process, not to
> share between multiple processes (whether they run the same or different
> scripts)
>
>> and written to the shared file?
>
> Nothing is ever written to a file.

Then how does it help the OP to propogate clibration values from one
program to another or from one program run to the next run?

> You could of course write python files from a python script (in fact I
> do this), but that's not what this pattern is about, AFAICS.


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Re: How to enter multiple, similar, dictionaries?

2023-12-11 Thread Grant Edwards via Python-list
On 2023-12-11, Chris Green via Python-list  wrote:
> Is there a way to abbreviate the following code somehow?
>
> lv = {'dev':'bbb', 'input':'1', 'name':'Leisure volts'}
> sv = {'dev':'bbb', 'input':'0', 'name':'Starter volts'}
> la = {'dev':'bbb', 'input':'2', 'name':'Leisure Amps'}
> sa = {'dev':'bbb', 'input':'3', 'name':'Starter Amps'}
> bv = {'dev':'adc2', 'input':0, 'name':'BowProp Volts'}
>
> It's effectively a 'table' with columns named 'dev', 'input' and
> 'name' and I want to access the values of the table using the variable
> name.

Named tuples stored in a dictionary or list?

> I could, obviously, store the data in a database (sqlite), I have some
> similar data in a database already but the above sort of format in
> Python source is more human readable and accessible.  I'm just looking
> for a less laborious way of entering it really.

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Re: Context without manager

2023-11-26 Thread Grant Edwards via Python-list
On 2023-11-27, Grant Edwards via Python-list  wrote:
> On 2023-11-26, Dieter Maurer via Python-list  wrote:
>
>> If you do not have this case (e.g. usually if you open the file
>> in a class's `__init__`), you do not use a context manager.
>
> He knows that. The OP wrote that he wants to use  that can
> _only_ be used by a context manager, but he wants that usage to be
> spread over various methods of a class he's writing.  So he's asking
> how to fool that  into working when he's not using a
> context manager.

I should probably have written "how to fool that  into
working when he's not using a 'with' statement"

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Re: Context without manager

2023-11-26 Thread Grant Edwards via Python-list
On 2023-11-26, Dieter Maurer via Python-list  wrote:

> If you do not have this case (e.g. usually if you open the file
> in a class's `__init__`), you do not use a context manager.

He knows that. The OP wrote that he wants to use  that can
_only_ be used by a context manager, but he wants that usage to be
spread over various methods of a class he's writing.  So he's asking
how to fool that  into working when he's not using a
context manager.

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Re: xor operator

2023-11-13 Thread Grant Edwards via Python-list
On 2023-11-14, Dom Grigonis via Python-list  wrote:
>
>> Except the 'any' and 'all' builtins are _exactly_ the same as bitwise
>> or and and applided to many bits. To do something "in line" with that
>> using the 'xor' operator would return True for an odd number of True
>> values and False for an even Number of True values.
>
> Fair point.
>
> Have you ever encountered the need for xor for many bits (the one
> that I am NOT referring to)? Would be interested in what sort of
> case it could be useful.

Yes, it's used all the time in low-level communications protocols,
where it's often implemented in hardware. But, it is also not at all
unusual to implement it in software.

It's also not that unusual for the "count-ones" part of the function
you're asking for to be implemented in hardware by a CPU having an
instruction that counts the number of 1 bits in a register.

GCC has a low-level builtins called __builtin_popcount() and
__builtin-popcountl() that counts the number of 1's in an unsigned
(long) int.


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Re: xor operator

2023-11-13 Thread Grant Edwards via Python-list
On 2023-11-13, Dom Grigonis via Python-list  wrote:

> I am not asking. Just inquiring if the function that I described
> could be useful for more people.
>
> Which is: a function with API that of `all` and `any` and returns
> `True` if specified number of elements is True.

I've got no objection to a function that counts True objects returned
by an iterator and returns True IFF count == .

I've got no objection to a function that counts True objects returned
by an iterator and returns True IFF count >= .

I've got no objection if that latter function short-circuits by
stopping the iteration and returning True when it has seen  true
objects.

I don't recall ever having a need for such a function in the 25 years
I've been writing Python code, but I'm not going to claim that nobody
else has a need for such a function.

I would object to that being called 'xor', and would fight to the
death (yes, I'm being hyperbolic) the addition of a builtin with the
name 'xor' that does what you describe.

> It is not a generalised `xor` in strict programatic space.

AFAICT, it's not nothing at all to do with 'xor' in any sense.

> I.e. NOT bitwise xor applied to many bits.  This is more in line
> with cases that `any` and `all` builtins are used.

Except the 'any' and 'all' builtins are _exactly_ the same as bitwise
or and and applided to many bits. To do something "in line" with that
using the 'xor' operator would return True for an odd number of True
values and False for an even Number of True values.

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Re: xor operator

2023-11-13 Thread Grant Edwards via Python-list
On 2023-11-13, Dom Grigonis via Python-list  wrote:
> Hi All,
>
> I think it could be useful to have `xor` builtin, which has API similar to 
> the one of `any` and `all`.
>
> * Also, it could have optional second argument `n=1`, which
> * indicates how many positives indicates `True` return.  For
> * complete flexibility 3rd argument could indicate if `the number`
> * is equal, greater, less, ... than `n`

I would expect "xor" to return true if there are an odd number of
trues, and false if there are an even number of trues.  It's not clear
to me what you're asking for.



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Re: Checking if email is valid

2023-11-07 Thread Grant Edwards via Python-list
On 2023-11-06, Greg Ewing via Python-list  wrote:
> On 7/11/23 7:45 am, Mats Wichmann wrote:
>> Continuing with the example, if you have a single phone number field, or 
>> let a mobile number be entered in a field marked for landline, you will 
>> probably assume you can text to that number.
>
> But if the site can detect that you've entered a mobile number into
> the landline field or vice versa and reject it, then it can figure out
> whether it can text to a given numner or not without you having
> to tell it!

Maybe. I'm pretty sure the last time I was in Australia, you could
send/recieve text messages from landalines. And I've had mobile number
that didn't support text messaging.

If you, as a web developer, want the user to enter a text-message
capable phone number, then ASK FOR THAT!


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Re: Checking if email is valid

2023-11-05 Thread Grant Edwards via Python-list
On 2023-11-05, D'Arcy Cain via Python-list  wrote:
> On 2023-11-05 00:39, Grant Edwards via Python-list wrote:
>> Definitely. Syntactic e-mail address "validation" is one of the most
>> useless and widely broken things on the Interwebs.  People who do
>> anything other than require an '@' (and optionally make you enter the
>> same @-containing string twice) are deluding themselves.
>
> And don't get me started on phone number validation.

I can see how the truley dim-witted might forget that other countries
have phone numbers with differing lengths and formatting/punctuation,
but there are tons of sites where it takes multiple tries when
entering even a bog-standard USA 10-0digit phone nubmer because they
are completely flummuxed by an area code in parens or hyphens in the
usual places (or lack of hyhpens in the usual places). This stuff
isn't that hard, people...

> The most annoying thing to me, though, is sites that reject names
> that have an apostrophe in them.  I hate being told that my name,
> that I have been using for over seventy years, is invalid.
>
> OK, now that I am started, what else?  Oh yah.  Look at your credit 
> card.  The number has spaces in it.  Why do I have to remove them.  If 
> you don't like them then you are a computer, just remove them.

Indeed. There is a tiny but brightly burning kernel of hate in my
heart for web sites (and their developers) that refuse to accept
credit card numbers entered with spaces _as_they_are_shown_on_the_card_!

I've concluded that using PHP causes debilitating and irreversible
brain damage.

> When do we stop working for computers and have the computers start 
> working for us?

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Re: Checking if email is valid

2023-11-04 Thread Grant Edwards via Python-list
On 2023-11-04, Michael Torrie via Python-list  wrote:
> On 11/4/23 02:51, Simon Connah via Python-list wrote:
>
>> Wow. I'm half tempted to make a weird email address to see how many
>> websites get it wrong.

In my experience, they don't have to be very weird at all.

>> Thank you for the link.
>
> Nearly all websites seem to reject simple correct email addresses
> such as myemail+sometext@example.domain.  I like to use this kind of
> email address when I can to help me filter out the inevitable spam
> that comes from companies selling off my address even after claiming
> they won't.

I've always suspected that's intentional. They refuse those sorts of
e-mail addresses because they know that's what they are used for. If
they allowed "plus suffixed" e-mail addresses, then all the crap they
want to send to you would go into /dev/null where it belongs -- and we
can't have that!

> So I suspect that nearly all websites are going to reject other
> kinds of weird email addresses you can create that are actually
> correct.

Definitely. Syntactic e-mail address "validation" is one of the most
useless and widely broken things on the Interwebs.  People who do
anything other than require an '@' (and optionally make you enter the
same @-containing string twice) are deluding themselves.

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Re: Checking if email is valid

2023-11-03 Thread Grant Edwards via Python-list
On 2023-11-02, Michael Torrie via Python-list  wrote:
> On 11/2/23 00:42, Simon Connah via Python-list wrote:
>
>> Valid as in conforms to the standard. Although having looked at the
>> standard that might be more difficult than originally planned.
>
> You'll have to read the relevant RFCs.  Lots of corner cases!  From what
> I can see virtually no one on the internet gets it right, judging by the
> number of times I have valid email addresses flagged as not valid by
> poor algorithms.

I've wondered if there are addresses that violate the RFC (and would
therefore be "correctly" rejected), but but in practice will work just
fine.  I've never spent enough time looking at the RFC to even propose
test cases for that...

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Re: Checking if email is valid

2023-11-01 Thread Grant Edwards via Python-list
On 2023-11-01, Chris Angelico via Python-list  wrote:
> On Thu, 2 Nov 2023 at 08:09, Grant Edwards via Python-list
> wrote:

>> Make sure it has an '@' in it.  Possibly require at least one '.'
>> after the '@'.
>
> No guarantee that there'll be a dot after the at.

Ah, I forgot about defaulting to a local domain if one is
omitted. Will MTAs do that these days?

> (Technically there's no guarantee of an at sign either, but email
> addresses without at signs are local-only, so in many contexts, you
> can assume there needs to be an at.)
>
> So the regex to match all valid email addresses that aren't
> local-only is... drumroll please...
>
> r"@"

Unless you want to support UUCP or X400 addresses...

:)




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Re: Checking if email is valid

2023-11-01 Thread Grant Edwards via Python-list
On 2023-11-01, Simon Connah via Python-list  wrote:

> I'm building a simple project using smtplib and have a
> question. I've been doing unit testing but I'm not sure how to check
> if an email message is valid.

Send an e-mail using it?  If the right person gets the e-mail, then
it's valid?

> Using regex sounds like a bad idea to me and the other options I
> found required paying for third party services.
>
> Could someone push me in the right direction please? I just want to
> find out if a string is a valid email address.

You'll have to define "valid".  Valid syntactically according to
?  Will be accepted by an SMTP server somewhere? Corresponds to
a real person?

Make sure it has an '@' in it.  Possibly require at least one '.'
after the '@'.

Trying to do anything more than that is just wasting your time and
annoying the mule.

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Re: Question(s)

2023-10-25 Thread Grant Edwards via Python-list
On 2023-10-25, o1bigtenor via Python-list  wrote:

> Haven't heard of a python IDE - - - doesn't mean that there isn't such - -
> just that I haven't heard of such. Is there a python IDE?

Seriously?  Now you're just trolling.

google.com/search?q=python+ide&oq=python+ide

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Re: Question(s)

2023-10-24 Thread Grant Edwards via Python-list
On 2023-10-24, o1bigtenor via Python-list  wrote:

> So how does one test software then?

That's what customers are for!



[Actually, that's true more often than it should be.]


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Re: Question(s)

2023-10-24 Thread Grant Edwards via Python-list
On 2023-10-24, Thomas Passin via Python-list  wrote:

> Something less ambitious than a full proof of correctness of an
> arbitrary program can sometimes be achieved.  The programming team
> for the Apollo moon mission developed a system which, if you would
> write your requirements in a certain way, could generate correct C
> code for them.

Er, what?

C didnt' exist until after the Apollo program was done.

FORTRAN, perhaps?

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Re: Question(s)

2023-10-24 Thread Grant Edwards via Python-list
On 2023-10-24, Dan Purgert via Python-list  wrote:
> On 2023-10-24, o1bigtenor wrote:
>> Greetings
>>
>> (Sorry for a nebulous subject but dunno how to have a short title for
>> a complex question.)
>> [...]
>> Is there a way to verify that a program is going to do what it is
>> supposed to do even before all the hardware has been assembled and
>> installed and tested?
>
> In short, no.
>
> Reality is a mess, and even if you've programmed/perfectly/ to the
> datasheets (and passed our unit-tests that are also based on those
> datasheets), a piece of hardware may not actually conform to what's
> written.  Maybe the sheet is wrong, maybe the hardware is faulty, etc.

And the specified customer requirements are usually wrong too. Sure,
the customer said it is supposed to do X, but what they actually
needed was Y.

And the protocol spec isn't quite right either.  Sure, it says "when A
is received reply with B", but what everybody really does is slighty
different, and you need to do what everybody else does, or the widget
you're talking to won't cooperate.

And floating point doesn't really work the way you think it
does. Sometimes it does, close-enough, for the test-cases you happened
to choose...





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Re: Question(s)

2023-10-24 Thread Grant Edwards via Python-list
On 2023-10-24, o1bigtenor via Python-list  wrote:

> Is there a way to verify that a program is going to do what it is
> supposed to do even before all the hardware has been assembled and
> installed and tested?

It depends on what you mean by "verify ...".  If you want to prove a
program correct (in the mathematical sense), then the practical answer
is no. It's possible to prove _some_ programs correct, but they tend to
be uselessly trivial.

For real programs, the best you can do is choose a good set of test
cases and test them.  If you can simulate the various inputs and
collect the outputs, then you can do testing before you have real
target hardware.


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Re: isinstance()

2023-08-04 Thread Grant Edwards via Python-list
On 2023-08-04, Chris Angelico via Python-list  wrote:
> On Sat, 5 Aug 2023 at 09:36, dn via Python-list  
> wrote:
>
>> Faced with a situation where an argument may be a scalar-value or an
>> iterable, I'll presume the latter, eg throw it straight into a for-loop.
>> If that fails (because the argument is a scalar), use try-except to
>> re-route the logic.
>
> That's great as long as you aren't expecting to handle strings.

If you do that, you're obviously not expecting to handle strings. The
problem happens when you're not expecting to handle strings, and you
get passed one anyway.

It's like the Spanish Inquisition...

> The string "spam" is sometimes equivalent to the list ["s", "p",
> "a", "m"] and sometimes not.

And b"ABCD" is sometimes equivalent to the list [65,66,67,68] and
sometimes not.

Been there, fell in that hole.

More than a few times. :/

Famous Last Words: "I wasn't expecting to handle strings -- but I
should have been..."

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Re: What is this TEST BANK stuff ?

2023-06-21 Thread Grant Edwards via Python-list
On 2023-06-21, Chris Angelico via Python-list  wrote:
> On Thu, 22 Jun 2023 at 02:54, Dan Kolis via Python-list
> wrote:
>>
>> Why do we tolerate this spam ?
>>
>> this seems most likely a way to inject viruses into people's workflow.
>>
>> That wiped out usenet. Ahh without an explaination; ( and it woudl have to 
>> be a good one ); what is the purpsoe of this, why is it here ?
>>
>> Can it be eliminated ?
>>
>
> Yes, follow the mailing list instead of the newsgroup. Most spam
> doesn't reach us over here at the list.
>
> Sign up here: https://mail.python.org/mailman/listinfo/python-list

If you want to stick with NNTP as your access protocol, you can follow
the list on gmane:

  nntp://news.gmane.io/gmane.comp.python.general

However, the list recently stopped accepting posts via gmane, so
you'll need to configure your nntp client to e-mail posts to that
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Re: Resolution of paths in tracebacks

2023-05-31 Thread Grant Edwards
On 2023-05-31, Vishal Chandratreya  wrote:
> When an exception occurs, the full path to the file from which it
> originates is displayed, but redundant elements are not removed. For
> instance:
> $ ./python ./foo
> Traceback (most recent call last):
>   File "/home/User/cpython/./foo", line 4, in 
> a()
>   File "/home/User/cpython/./foo", line 3, in a
> def a(): raise ValueError
> ValueError
> This happens because the function _Py_abspath (in Python/fileutils.c)
> appends relative_path_to_file to absolute_path_to_current_working_directory.
> Not sure if this should be treated as a bug, because the definition of
> 'absolute path' is not clear. Does it mean a path starting from the root
> directory, or a path without redundant elements?

The former:

  
https://www.linuxfoundation.org/blog/blog/classic-sysadmin-absolute-path-vs-relative-path-in-linux-unix


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Re: Tkinter docs?

2023-05-30 Thread Grant Edwards
On 2023-05-26, Rob Cliffe via Python-list  wrote:

> Grant, I may well buy one of the books you suggested.

I haven't had look at either of the newer books, but I got a lot of
good out of the Grayson book (20 years ago).  I also had a Tcl/Tk book
that I found useful even when usng tkinter, but it's even older than
the Grayson one...
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Re: Invalid literal for int() with base 10?

2023-05-26 Thread Grant Edwards
On 2023-05-26, Grant Edwards  wrote:
> On 2023-05-25, Kevin M. Wilson via Python-list  wrote:
>
>> Ok, I'm not finding any info. on the int() for converting a str to
>> an int (that specifies a base parameter)?!
>
> Where are you looking?
>
>   https://docs.python.org/3/library/functions.html#int

And don't forget about the help() function:

$ python
Python 3.11.3 (main, May  8 2023, 09:00:58) [GCC 12.2.1 20230428] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 
>>> help(int)
Help on class int in module builtins:

class int(object)
 |  int([x]) -> integer
 |  int(x, base=10) -> integer
 |  
 |  Convert a number or string to an integer, or return 0 if no arguments
 |  are given.  If x is a number, return x.__int__().  For floating point
 |  numbers, this truncates towards zero.
 |  
 |  If x is not a number or if base is given, then x must be a string,
 |  bytes, or bytearray instance representing an integer literal in the
 |  given base.  The literal can be preceded by '+' or '-' and be surrounded
 |  by whitespace.  The base defaults to 10.  Valid bases are 0 and 2-36.
 |  Base 0 means to interpret the base from the string as an integer 
literal.
 |  >>> int('0b100', base=0)
 |  4
 |  
 |  Built-in subclasses:
 |  bool
 |  
 |  Methods defined here:
 |  
 |  __abs__(self, /)
 |  abs(self)
 |  
 |  __add__(self, value, /)
 |  Return self+value.
 |  
[...]

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Re: Invalid literal for int() with base 10?

2023-05-25 Thread Grant Edwards
On 2023-05-25, Kevin M. Wilson via Python-list  wrote:

> Ok, I'm not finding any info. on the int() for converting a str to
> an int (that specifies a base parameter)?!

Where are you looking?

  https://docs.python.org/3/library/functions.html#int

> The picture is of the code I've written... And the base 10 paradigm
> involved??

I've no clue what that sentence means.

> years = int('y') # store for calculationValueError:
> invalid literal for int() with base 10: 'y'What is meant by "invalid
> literal"?

It means that the string 'y' isn't an integer literal.  The strings
'123' and '-4' are integer literals.

  
https://docs.python.org/3/reference/expressions.html?highlight=integer%20literal#literals

> I'm trying to convert srt to int, and I didn't know I needed to
> specify the base.

You don't need to unless you want a base other than 10.

> Plus I haven't read anything that I need to specify the base for the int().

Don't know what you mean there.

> Attached is the code, showing the code and the execution of said
> code.

Sorry, I don't see attachments. Include code in posts.

> "When you pass through the waters, I will be with you: and
>  when you pass through the rivers, they will not sweep
>  over you. When you walk through the fire, you will not be burned:
>  the flames will not set you ablaze." Isaiah 43:2

Huh?


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Re: Tkinter docs?

2023-05-23 Thread Grant Edwards
On 2023-05-24, Rob Cliffe via Python-list  wrote:
> I have recently started converting a large project to tkinter, starting 
> with zero knowledge of tkinter.  (You are free to think: BAD IDEA. 😁)

Well, you could be translating them to Tcl/Tk -- so on the scale of
bad ideas, your's barely registers.

> I am well aware that adopting a new tool always involves a learning 
> curve, and that one is prone to think that things are more difficult 
> than they are/should be, and to belly-ache about it, and that in a year 
> from now I'll probably wonder what I'm fussing about.
> Nonetheless ISTM that there is a particular problem with tkinter:
>
>   There doesn't seem to be any decent documentation for it anywhere.

Back in the day, the Grayson book was the definitive reference:

   https://www.amazon.com/Python-Tkinter-Programming-John-Grayson/dp/1884777813/

It's 20+ years old now, so the version of Python it uses is pretty
ancient, and I presume Tk has also changed a bit over the years, so...

There are a couple recent books, but I haven't looked at them:

   
https://www.amazon.com/Modern-Tkinter-Busy-Python-Developers-dp-1999149564/dp/1999149564/

   
https://www.amazon.com/Python-GUI-Programming-Tkinter-user-friendly/dp/1801815925/

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Re: What to use instead of nntplib?

2023-05-22 Thread Grant Edwards
On 2023-05-22, Keith Thompson  wrote:

> My understanding is that nntplib isn't being erased from reality,
> it's merely being removed from the set of modules that are provided
> by default.
>
> I presume that once it's removed from the core, it will still be
> possible to install it via pip or some other mechanism.

If somebody rescues the code and puts it in Pypi (assuming the
copyright owner allows that). IIRC, somebody is trying to do that, but
there some contention because Pypi won't allow the use of the name
"nntplib" for the package because it conflicts with a library builtin.
>
> import warnings
> warnings.filterwarnings("ignore", category=DeprecationWarning)
> import nntplib

Yep, thanks. That at least prevents the warning from messing up my
slrn screen. :)

> If my understanding is correct, why is this such a big problem?

It's not a "big" problem, but something that "just worked" with any
Python installation now requires that the user install an extra
package. If they don't already have pip, then they have to install
that first. And then they have to do it again, because the first time
they installed pip for the wrong version of python. [I don't really
get how that happens, but there seem to be a constant stream of
postings from people with that problem.]

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Re: What to use instead of nntplib?

2023-05-22 Thread Grant Edwards
On 2023-05-21, Retrograde  wrote:

> Who ever came up with "Removing dead batteries" as a slogan, when
> some of those batteries still work perfectly well, needs to rethink
> it. Go ahead and remove code that no longer works, OK.  But removing
> unpopular modules?  That undercuts the entire philosophy of the
> platform, in my opinion.

And one of the metrics of "popularity" seems to be "activity"
(e.g. changes committed).  For things that have been around for 20+
years and have all the features they need and all of the bugs fixed
(and are now very stable) that lack of "activity" is interpreted as
"unpopular" regardless of how many people are using the module.

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Re: Tkinter (related)~

2023-05-18 Thread Grant Edwards
On 2023-05-19, Cameron Simpson  wrote:
> On 18May2023 12:06, Jack Dangler  wrote:
>>I thought the OP of the tkinter thread currently running may have 
>>needed to install the tkinter package (since I had the same missing 
>>component error message), so I tried to install the package on to my 
>>Ubu laptop -
>>
>>pip install tkinter
>>Defaulting to user installation because normal site-packages is not 
>>writeable
>>ERROR: Could not find a version that satisfies the requirement tkinter 
>>(from versions: none)
>>ERROR: No matching distribution found for tkinter
>>
>>Is there an alternate path to installing this?
>
> Usually tkinter ships with Python because it is part of the stdlib.
>
> On some platforms eg Ubuntu Linux the stdlib doesn't come in completely 
> unless you ask - a lot of stdlib packages are apt things you need to ask 
> for. On my Ubunut here tkinter comes from python3-tk. So:
>
>  $ sudo apt-get install python3-tk

And in general, on Linux systems, you'll be better off in the long run
if you use the distro's package manager to install Python packages
instead of using pip. If there is no distro package, you're usually
also better off using 'pip install --user' so that pip isn't messing
about with directories that are normally managed by the distro's
package manager.

When I do have to resort to using pip in install something, I always
do a --dry-run first and make a note of any dependancies that pip is
going to try to install -- so I can install those using the package
manager if possible.

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Re: Learning tkinter

2023-05-18 Thread Grant Edwards
On 2023-05-12, Rob Cliffe via Python-list  wrote:
>
> Python 3.8.3 (tags/v3.8.3:6f8c832, May 13 2020, 22:20:19) [MSC v.1925 32 
> bit (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import tkinter
> >>> tkinter.messagebox
> Traceback (most recent call last):
>    File "", line 1, in 
> AttributeError: module 'tkinter' has no attribute 'messagebox'
> >>>

$ python
Python 3.11.3 (main, May  8 2023, 09:00:54) [GCC 12.2.1 20230428] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tkinter
>>> from tkinter import messagebox
>>> messagebox

>>> 


> Why is this?

Dunno.
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Re: What to use instead of nntplib?

2023-05-16 Thread Grant Edwards
On 2023-05-16, Chris Green  wrote:
> Grizzy Adams  wrote:
>> Tuesday, May 16, 2023  at 9:26, Alan Gauld wrote:
>> Re: What to use instead of nntplib? (at least in part)
>> 
>> >On 15/05/2023 22:11, Grant Edwards wrote:
>> >> I got a nice warning today from the inews utility I use daily:
>> >> 
>> >> DeprecationWarning: 'nntplib' is deprecated and slated for removal in 
>> >> Python 3.13
>> >> 
>> >> What should I use in place of nntplib?
>> 
>> >I'm curious as to why nntplib is deprecated? Surely there are still a
>> >lot of nntp servers around
>> 
>> there must be this list is mirrored on one, and AFAICS some pythoners use 
>> that 
>> way to post (over the list)
>
> Yes, me for one, a good newsreader is really a wonderful way to manage
> technical 'lists' like this one.

IMO, there's nothing better. Newsreaders were designed from the
beginning to deal with the sort of traffic and usage patterns seen in
mailing lists. Using an MUA (even combined with something like
procmail) and folders/labels is just a pale imitation of a good
newsreader.

> Usenet news is still very much alive though a minority interest now
> I suspect.

This list's decision to stop accepting postings via news.gmane.io is
what prompted me to write my own "inews" application in Python that
uses SMTP for some groups and NNTP for others when I "post" via slrn.

I probably use NNTP more to access mailing lists via gmane than I use
it for accessing the "real" Usenet groups.

NNTP is not just for Usenet...






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Re: What to use instead of nntplib?

2023-05-16 Thread Grant Edwards
On 2023-05-16, Alan Gauld  wrote:
> On 16/05/2023 10:06, Cameron Simpson wrote:
>
>>> I'm curious as to why nntplib is deprecated? Surely there are still a
>>> lot of nntp servers around, both inside and outside corporate firewalls?

Anything not used to develop AI is going to be depricated. An AI told
me, so it must be true.

>>> Is there a problem with the module or is it just perceived as no longer
>>> required?

Two issues were cited:

 1. It's too stable, bug-free, and feature-complete. IOW "no
activity". Apparently, people equate "activity" with "usage".

 2. A problem with automated testing, since there's no server side
support. Though testing a module's client implementation by having
it talk to a module's server implementation seems like a
singularly bad idea.


>> See PEP 594: https://peps.python.org/pep-0594/
>
> Thanks Cameron.
> A scary list; I must have a dozen projects from the late 90s still
> live that are using many of these! I'm glad I'm retired and won't
> be the one who has to fix 'em :-)

It has been pointed out to me that Perl still has a supported NNTP
library. That stung. However, it's a CPAN module, which is more
equivalent to PyPI than to the standard library, so I guess that it
isn't as bad a loss of face as I feared.

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Re: What to use instead of nntplib?

2023-05-15 Thread Grant Edwards
On 2023-05-15, Skip Montanaro  wrote:
>> I got a nice warning today from the inews utility I use daily:
>>
>> DeprecationWarning: 'nntplib' is deprecated and slated for
>> removal in Python 3.13
>>
>> What should I use in place of nntplib?
>
> I'd recommend creating a PyPI project with the existing 3.12 code,
> then using that from 3.13 onward.

That may be the easiest option. :/

I did some googling for utilities to post articles to NNTP servers and
found "postnews". Of course it's written in Python and depends on
nntplib...

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What to use instead of nntplib?

2023-05-15 Thread Grant Edwards
I got a nice warning today from the inews utility I use daily:

DeprecationWarning: 'nntplib' is deprecated and slated for removal in 
Python 3.13

What should I use in place of nntplib?

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Re: Is npyscreen still alive?

2023-04-24 Thread Grant Edwards
On 2023-04-24, Mats Wichmann  wrote:
> On 4/24/23 10:32, Grant Edwards wrote:
>
>> However... I just realized that Python's curses support is missing two
>> huge chunks: both menu and form support are not there.  I guess that
>> explains why people feel the need to write high-level UI wrappers for
>> Python curses: the high level stuff that curses does support is
>> missing from the Python bindings.
>> 
>> Adding a curses UI for my app might not be feasible after all...
>
> I guess it's also worth mentioning that Python curses doesn't work out 
> of the box on Windows - because the actual curses library isn't commonly 
> present on Windows. It's not hard to get hold of builds (check PyPI) but 
> that means it's no longer "standard".

That's a good point. I neglected to mention that the use case for
curses UI app is to run on headless Linux servers. It needs to work
when run on a Linux by a user logged in via Putty on Windows, but I
have no need to execute the application in curses-mode on Windows.

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Re: Python curses missing form library?

2023-04-24 Thread Grant Edwards
On 2023-04-24, Alan Gauld  wrote:
> On 24/04/2023 17:26, Grant Edwards wrote:
>> Does the Python curses support in the standard library not include
>> support for the curses form library? It seems to include support for
>> the panel library, but I can't find any mention of the form library.
>
> I don't believe so. If you are building terminal based form-type
> apps the best bet seems to be urwid. I haven't used it in anger
> but the beginner docs I saw looked promising.

urwid does indeed look nice, but it would require doing the whole
bundling and installing thing. I was hoping to avoid that by sticking
with stdlib and curses.

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Re: Is npyscreen still alive?

2023-04-24 Thread Grant Edwards
On 2023-04-24, Grant Edwards  wrote:

> The other big advantage of an ncurses program is that since curses
> support is in the std library, a curses app is simpler to
> distribute.  Right now, the application is a single .py file you
> just copy to the destination machine and run.  It supports
> command-line use and a Tk GUI. I can add an ncurses "CUI" without
> having to either adopt a more complex bundling mechanism that
> requires it to be "installed" or require that users install
> dependencies via pip/apt/yum/whatever.

However... I just realized that Python's curses support is missing two
huge chunks: both menu and form support are not there.  I guess that
explains why people feel the need to write high-level UI wrappers for
Python curses: the high level stuff that curses does support is
missing from the Python bindings.

Adding a curses UI for my app might not be feasible after all...

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Python curses missing form library?

2023-04-24 Thread Grant Edwards
Does the Python curses support in the standard library not include
support for the curses form library? It seems to include support for
the panel library, but I can't find any mention of the form library.

I see in the docs that menu support is still missing. :/

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Re: Is npyscreen still alive?

2023-04-24 Thread Grant Edwards
On 2023-04-24, Michael Torrie  wrote:
> On 4/21/23 15:57, Barry wrote:
>
>> Maybe this, recently lwn.net article,
>> https://textual.textualize.io/ I was planning to check it out.
>
> Textual definitely looks slick and modern.  And with a modern
> terminal emulator it works quite well and is responsive.  I'd
> definitely consider it for a TUI.
>
> But on the Linux console, or on an older terminal, not so much.
> Textual's really designed for smallish unicode fonts in a windowed
> environment, not any kind of real, old-school text mode.  Just
> something to keep in mind.  99% of terminal users are using a modern
> terminal emulator these days, with full color and unicode, which is
> the target of textual.

Is putty running on Windows a "modern terminal emulator" in this
context?  After observing some of the local IT types work, I suspect
that will be a common use-case for the app I'm working on.

> Curses-based programs don't look great on anything, but they do look
> consistent on more primitive terminals.

The other big advantage of an ncurses program is that since curses
support is in the std library, a curses app is simpler to distribute.
Right now, the application is a single .py file you just copy to the
destination machine and run.  It supports command-line use and a Tk
GUI. I can add an ncurses "CUI" without having to either adopt a more
complex bundling mechanism that requires it to be "installed" or
require that users install dependencies via pip/apt/yum/whatever.

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Is npyscreen still alive?

2023-04-21 Thread Grant Edwards
I recently googled across the ncurses application framework npyscreen,
and was thinking about giving it a try for a small but real project
(something that would be distributed to customers), but I'm a bit
concerned that npyscreen no longer "alive".

The pypi page says the homepage is http://www.npcole.com/npyscreen/,
which then points to a Google Code page at 
https://code.google.com/archive/p/npyscreen/.

That page says the official repo is at https://bitbucket.org/npcole/npyscreen
which returns a 404.

There seems to be a copy in Github at 
https://github.com/npcole/npyscreen/commits/master,
but the last commit was almost 4 years ago.

Maybe it "just works" and is suitable for production?




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Re: Weak Type Ability for Python

2023-04-13 Thread Grant Edwards
On 2023-04-13, Cameron Simpson  wrote:
> On 12Apr2023 22:12, avi.e.gr...@gmail.com  wrote:
>
>>I suspect the OP is thinking of languages like PERL or JAVA which guess 
>>for you and make such conversions when it seems to make sense.
>
> JavaScript guesses. What a nightmare.

So does PHP. What's really impressive is that it never seems to guess
correctly. :)
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Re: Weak Type Ability for Python

2023-04-12 Thread Grant Edwards
On 2023-04-12, Ali Mohseni Roodbari  wrote:
> Hi all,
> Please make this command for Python (if possible):
>
 x=1
 y='a'
 wprint (x+y)
 1a

If that's what you want, use PHP or some other language. Don't try to ruin 
Python.

> In fact make a new type of print command which can print and show strings
> and integers together.


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Re: Dataclasses, immutability(?), and ChatGPT

2023-04-12 Thread Grant Edwards
On 2023-04-12, Roel Schroeven  wrote:

>> Huh? If we'd been discussing namedtuples over (say) dictionaries, I'd 
>> perhaps have accepted the reply.
>
> ChatGPT is wrong.
>
>> Anything I've 'missed'?
>> - or a salutary tale of not depending upon ChatGPT etc?

> You didn't miss anything, ChatGPT is wrong. The thing to look out for is 
> that when ChatGPT is wrong, it sounds just as convincing as when it's 
> right; there is no indication in it's tone or style that it's making 
> things up.

Yep, that's how ChatGPT works. It's a program to generate output
language that sounds right based on a huge training set of
text. Whether that "right sounding" language agrees with real world
facts or not is irrelevent to the language-generating algorithm.

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Re: Windows Gui Frontend

2023-04-02 Thread Grant Edwards
On 2023-04-02, Michael Torrie  wrote:
> On 4/2/23 05:09, Dietmar Schwertberger wrote:
>> I also did evaluate all the GUI builder from time to time between
>> 2000 and 2016 to find one that I could recommend to colleagues,
>> but could not find one. Then I started contributing to wxGlade
>> and I can say that since a few years it's as easy again to
>> build GUIs as it was with VB6.
>
> [...]
>
> But any modern GUI toolkit has sizers and layout managers. If you're
> manually placing elements you cannot deal with HiDPI or changing window
> sizes.

Ah, that's the brilliant thing about VB6 apps! They only work properly
on machines with the same resoultion and display/font configuration as
the developer.

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Re: Windows Gui Frontend

2023-04-01 Thread Grant Edwards
On 2023-04-01, Thomas Passin  wrote:

> Having worked with both, I'd rather use PyQt, although Tk might be 
> easier to get a toy app going with.  Both editing windows and packing 
> are easier for me to understand with PyQt, for one thing.

With tk it is _very_ easy to get small apps going. As the apps get
larger and more complex, I find it easier to use wxPython or pyGTK
(never tried pyQt).  However, if you want to package that small app
using cxfreeze (or whatever) tk tends to produce pretty large bundles
compared to others.

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Re: built-in pow() vs. math.pow()

2023-03-30 Thread Grant Edwards
On 2023-03-30, Thomas Passin  wrote:
> On 3/30/2023 5:15 AM, Andreas Eisele wrote:

>> [...] I was unpleasantly surprised that math.pow() does not have
>> this feature, hence "from math import *" overwrites the built-in
>> pow() function with a function that lacks functionality. [...]
>
> Not an answer to your question, but it's better not to use "import *".
> It's usually better to import just the names you actually need.

Or to imporot math and then use math.pow().

Unfortunately, the official Python documentation always seems to
assume you do "from  import *". I think that leads people to
believe it's a good practice when, in fact, it's a frequent source of
trouble as the OP found out.

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Re: What kind of "thread safe" are deque's actually?

2023-03-29 Thread Grant Edwards
On 2023-03-29, Jack Dangler  wrote:
>
>>  data = sorted(data)
>
> Sorry for any injected confusion here, but that line "data = 
> sorted(data)" appears as though it takes the value of the variable named 
> _data_, sorts it and returns it to the same variable store, so no copy 
> would be created. Am I missing something there?

Yes, you're missing the basics of what an assignment does in Python
and how objects work.  Python doesn't have such a thing as "a variable
st store".

The assignment operator binds a name to an object.

The 'sorted(data)' expression creates a new object containing a sorted copy of 
'data'.

The assignment then binds the name "data" to that new object.

The old, unsorted object then becomes inaccessable (unless there are
other names bound to it, or it's being otherwise used). At some point
that old, unsorted object will "go away" completely and cease to exist.

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