🌐 Mailman 3 February 2023 - Python-list - python.org

putting JUNK at the end of a [.py] file
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

in a LaTeX file, after the (1st) \end{document} line, i can put any random Junk i want (afterwards) until the end of the file. Is there a similar Method for a .py file ? Since i know of no such trick, i sometimes put this (below) at the end of a .py file. dummy= (""" junk and more junk words in Dict 239 words in Dict ((( notes or Code fragmetns ))) """ ) ** maybe i don't need the dummy= but it looks better.

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lxml with python-3.12.0a5
by Robin Becker Feb. 24, 2023

Feb. 24, 2023

I'm trying to test python-3.12.0a5 and need to install lxml. My wheel build for lxml fails with errors like this src/lxml/etree.c: In function ‘__Pyx_PyIndex_AsSsize_t’: src/lxml/etree.c:270404:45: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’ 270404 | const digit* digits = ((PyLongObject*)b)->ob_digit; | ^~ I'm using archlinux which has gcc 12.2.1. I tested and lxml will build with 3.11.2. I imagine this is part of ongoing changes to the python core, but perhaps there's some simple workaround. Anyone know how to get around this problem. I did try rebuilding the cpython stuff using make, but that also failed. -- Robin Becker

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Error-Msg Jeannie's charming, teasing ways
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

Python's Error-Msg genie (Jeannie) is cute and fickle... She sometimes teases me by not telling me what the VALUE of the "int" is ( "That's for me to know, and for you to find out!" ) as in: TypeError: can only concatenate str (not "int") to str Other times, she (Jeannie) gives me a helpful comment: ABCD (above and beyond... her job desc.) if (x=0): ^^^ SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '='? Maybe you'd share other EXAMPLES of her charming, teasing ways??? is there a Tool that can scan my code and tell me such (wink,wink) type suggestions???? ----------- [Maybe you'd like to rewrite this line as ....... ?] [Might i interest you in the coding-style wherein ...... ?] etc? https://stackoverflow.com/questions/26000198/what-does-colon-equal-in-pytho… There is new syntax := that assigns values to variables as part of a larger expression. It is affectionately known as “the walrus operator” due to its resemblance to the eyes and tusks of a walrus.

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Introspecting the variable bound to a function argument
by Anton Shepelev Feb. 23, 2023

Feb. 23, 2023

Hello, all. Does Python have an instrospection facility that can determine to which outer variable a function argument is bound, e.g.: v1 = 5; v2 = 5; def f(a): print(black_magic(a)) # or black_magic('a') f(v1) # prints: v1 f(v2) # prints: v2 -- () ascii ribbon campaign -- against html e-mail /\ www.asciiribbon.org -- against proprietary attachments

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Re: semi colonic
by Greg Ewing Feb. 23, 2023

Feb. 23, 2023

On 23/02/23 1:58 pm, avi.e.gross(a)gmail.com wrote: > Would anything serious break if it was deprecated for use as a statement > terminator? Well, it would break all the code of people who like to write code that way. They might get a bit miffed if we decide that their code is not serious. :-) On the other hand, if they really want to, they will still be able to abuse semicolons by doing this sort of thing: a = 5; pass b = 7; pass c = a * b; pass Then everyone will know it's some really serious code! -- Greg

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Re: LRU cache
by Dino Feb. 23, 2023

Feb. 23, 2023

Thank you Mats, Avi and Chris btw, functools.lru_cache seems rather different from what I need, but maybe I am missing something. I'll look closer. On 2/14/2023 7:36 PM, Mats Wichmann wrote: > On 2/14/23 15:07, Dino wrote: >>

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Re: Add angle brackets for required args in argparse
by Mark Bourne Feb. 23, 2023

Feb. 23, 2023

scruel tao wrote: > If we have the following code: > ``` > parser = argparse.ArgumentParser(description="test") > parser.add_argument('path') > ``` > > Run it without args, will get error message: > ``` > usage: test.py [-h] path > test.py: error: the following arguments are required: path > ``` > > However, I hope the message can be as the following: > ``` > usage: test.py [-h] <path> > test.py: error: the following arguments are required: path > ``` The `metavar` argument to `add_argument` can be used to control how an argument is represented in the usage text: ``` import argparse parser = argparse.ArgumentParser(description='test') parser.add_argument('path', metavar='<path>') parser.parse_args() ``` Which results in: ``` usage: test.py [-h] <path> test.py: error: the following arguments are required: <path> ``` > Or might can consider to provide a way to let user have there own style, like: > ``` > usage: test.py [-h] path > ``` It's also possible to create a custom help formatter, overriding appropriate methods to control the formatting. For example: ``` import argparse class CustomHelpFormatter(argparse.HelpFormatter): def _get_default_metavar_for_positional(self, action): default = super()._get_default_metavar_for_positional(action) return f'<{default}>' parser = argparse.ArgumentParser( description='test', formatter_class=CustomHelpFormatter) parser.add_argument('path') parser.parse_args() ``` Which results in: ``` usage: test.py [-h] <path> test.py: error: the following arguments are required: path ``` That's a bit closer to what you asked for, since the required argument shown in the error message doesn't include the angle brackets. It also avoids needing to specify a `metavar` for every positional argument. However, it is overriding a non-public method of the `HelpFormatter` class, so might not work across all Python versions if the name or signature of that method changes (even if it does work with all current versions, it might break in future). -- Mark.

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Python + Vim editor
by Hen Hanna Feb. 22, 2023

Feb. 22, 2023

what editor do you (all) use to write Python code? (i use Vim) yesterday (?) i started noticing this with Bing search .... e.g. i type [synonym rich] whch gives several synonyms, and so (next) i try to replace [rich] by something like Affluent so i try to hit [<-] to erase [rich] but i can't... the [text entering] box is frozen. so i give up and go to Google.

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Re: is [comprehension] the right word???
by Hen Hanna Feb. 22, 2023

Feb. 22, 2023

On Monday, February 20, 2023 at 5:45:39 PM UTC-8, Paul Rubin wrote: > Hen Hanna <henh...(a)gmail.com> writes: > > is [comprehension] the right word??? > Yes, it comes from math, particularly set theory. An expression like > > { n | n:integer, n mod 2 = 0 } > > is called a set comprehension, and then one there denotes the set of all > even integers. Axioms saying that the above denotes a legitimate set > are called comprehension axioms. In ZFC (an axiomitization of set > theory widely used in math), there is an infinite schema of such axioms. > > The Haskell language used a notation inspired by this for "list > comprehensions", and Python list (and later dictionary etc.) > comprehensions were inspired by Haskell's version. thank you .... i did a search thru Google.Books and found just 1 hit (before 1970). The Cambridge History of Later Greek and Early Medieval ... - Page 133 books.google.com › books A. H. Armstrong · 1967 FOUND INSIDE – PAGE 133 Too powerful , in fact : in 1902 , Russell showed that it is inconsistent , since it implies Russell's Antinomy ( see Russell's letter to Frege in van Heijenoort 1967 ) . Law V is close to what has become known as the Set Comprehension Principle (SCP) ........................

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Creating logs with Python
by Bibi Feb. 22, 2023

Feb. 22, 2023

Hello I want to store and make available as part of my project, logs, for access to data. Do you have any proposals? Kind regards

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