Mailman 3 August 2023 - Python-list

>>> %matplotlib inline results in SyntaxError: invalid syntax
by Mike S Dec. 25, 2023

Dec. 25, 2023

I have installed Python 3.4.4 on XPSP3 and am trying to work my way through this tutorial. A Complete Tutorial on Ridge and Lasso Regression in Python http://www.analyticsvidhya.com/blog/2016/01/complete-tutorial-ridge-lasso-r… In Step 2 "Why Penalize the Magnitude of Coefficients?" we are shown this code: #Importing libraries. The same will be used throughout the article. import numpy as np import pandas as pd import random import matplotlib.pyplot as plt %matplotlib inline I get an error on the last line. I am running this code in Idle Python 3.4.4 Shell... Python 3.4.4 (v3.4.4:737efcadf5a6, Dec 20 2015, 19:28:18) [MSC v.1600 32 bit (Intel)] on win32 Type "copyright", "credits" or "license()" for more information. >>> import numpy as np >>> import pandas as pd >>> import random >>> import matplotlib.pyplot as plt >>> %matplotlib inline SyntaxError: invalid syntax What am I doing wrong? Suggested reading? TIA, Mike

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Why do I always get an exception raised in this __init__()?
by Chris Green Sept. 1, 2023

Sept. 1, 2023

I'm obviously doing something very silly here but at the moment I can't see what. Here's the code:- #!/usr/bin/python3 # # # GPIO # import gpiod # # # Simple wrapper class for gpiod to make set and clearing outputs easier # class Gpiopin: def __init__(self, pin): # # # scan through the GPIO chips to find the line/pin we want # for c in ['gpiochip0', 'gpiochip1', 'gpiochip2', 'gpiochip3']: chip = gpiod.Chip(c) for l in range(32): line = chip.get_line(l) if pin in line.name(): print("Found: ", line.name()) return else: raise ValueError("Can't find pin '" + pin + "'") def print_name(self): print (self.line.name()) def set(self): self.line.set_value(1) def clear(self): self.line.set_value(0) This is by no means the final code, the print() in the __init__() is just a diagnostic for example. However I really can't understand why I see the following when I try it:- >>> import ngp >>> ngp.Gpiopin("P9_23") Found: P9_23 Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/home/chris/.cfg/hosts/bbb/bin/ngp.py", line 24, in __init__ return ValueError: Can't find pin 'P9_23' >>> Does a return in __init__() not do what I think it does? How else could/should I do this? -- Chris Green ·

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Re: What sort of exception when a class can't find something?
by Chris Green Aug. 31, 2023

Aug. 31, 2023

Several helpful replies, thank you all. -- Chris Green ·

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What sort of exception when a class can't find something?
by Chris Green Aug. 31, 2023

Aug. 31, 2023

What sort of exception should a class raise in __init__() when it can't find an appropriate set of data for the parameter passed in to the class instantiation? E.g. I have a database with some names and address in and have a class Person that gets all the details for a person given their name. .... .... person.Person('Fred') ... ... If Fred doesn't exist in the database what sort of exception should there be? Is it maybe a ValueError? -- Chris Green ·

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f-string error message
by Rob Cliffe Aug. 31, 2023

Aug. 31, 2023

I am currently using Python 3.11.4. First I want to say: f-strings are great! I use them all the time, mostly but by no means exclusively for debug messages. And in 3.12 they will get even better. And the improved error messages in Python (since 3.9) are great too! Keep up the good work. However the following error message confused me for a while when it happened in real code: >>> import decimal >>> x=42 >>> f"{x:3d}" ' 42' >>> x=decimal.Decimal('42') >>> f"{x:3d}" Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: invalid format string I understand that this is an error: I'm telling the f-string to expect an integer when in fact I'm giving it a Decimal. And indeed f"{x:3}" gives ' 42' whether x is an int or a Decimal. However, to my mind it is not the format string that is invalid, but the value supplied to it. Would it be possible to have a different error message, something like ValueError: int expected in format string but decimal.Decimal found Or am I missing something? Best wishes Rob Cliffe

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Using "textwrap" package for unwrappable languages (Japanese)
by c.buhtz＠posteo.jp Aug. 30, 2023

Aug. 30, 2023

Hi, I do use "textwrap" package to wrap longer texts passages. Works well with English. But the source string used is translated via gettext before it is wrapped. Using languages like Japanese or Chinese would IMHO result in unwrapped text. Japanese rules do allow to break a line nearly where ever you want. How can I handle it with "textwrap"? At runtime I don't know which language is really used. So I'm not able to decide using "textwrap" or just inserting "\n" every 65 characters. Another approach would be to let the translators handle the line breaks. But I would like to avoid it because some of them don't know what "\n" means and they don't know the length rule (in my case 65 characters). Any ideas about it? Kind Christian

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Generating documentation with Sphinx
by Jason Friedman Aug. 28, 2023

Aug. 28, 2023

I have two questions, please (this is after reading https://docs.readthedocs.io/en/stable/guides/cross-referencing-with-sphinx.… ). This is my project structure: my_project api stuff1.py stuff2.py lib stuff3.py stuff4.py main_application.py In my_project/main_application.py I have two functions: def construct_response(exit_code: int, message: str) -> Response: """ Construct a Flask-suitable response :param exit_code: 0 or something else :param message: something useful :return: a Flask-suitable response """ @app.route(f"/{version}/<page>", methods=[GET, POST]) def serve(page) -> Response: """ Do some stuff and return 200 or 500 :param page: this is a REST endpoint we are advertising to callers :return: a Flask Response generated by construct_response """ Question 1: how do I embed in the serve function docstring a link to the construct_response function? Question 2: how do I embed in, for example, lib/stuff3.py, a link to the construct_response function? I tried: :ref:`my_project/api/stuff1:construct_response` but that gives an undefined label warning.

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Co-op Group: Django web framework
by dn Aug. 28, 2023

Aug. 28, 2023

Are you interested in learning Django? Would like to improve your Django knowledge and skills? Have you been picking-up Django piecemeal, and need to consolidate and clarify? Do you know some Django and would like to acquire mentoring and coaching skills? If so, please join us to form a Learning Django Co-op. RSVP at https://www.meetup.com/nzpug-auckland/events/295727130/ -- Regards =dn

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[RELEASE] Python 3.11.5, 3.10.13, 3.9.18, and 3.8.18 is now available
by Łukasz Langa Aug. 24, 2023

Aug. 24, 2023

There’s security content in the releases, let’s dive right in. gh-108310 <https://github.com/python/cpython/issues/108310>: Fixed an issue where instances of ssl.SSLSocket <https://docs.python.org/release/3.10.13/library/ssl.html#ssl.SSLSocket> were vulnerable to a bypass of the TLS handshake and included protections (like certificate verification) and treating sent unencrypted data as if it were post-handshake TLS encrypted data. Security issue reported as CVE-2023-40217 1 <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40217> by Aapo Oksman. Patch by Gregory P. Smith. Upgrading is highly recommended to all users of affected versions. <https://discuss.python.org/t/python-3-11-5-3-10-13-3-9-18-and-3-8-18-is-now…>Python 3.11.5 Get it here: https://www.python.org/downloads/release/python-3115/ This release was held up somewhat by the resolution of this CVE, which is why it includes a whopping 328 new commits since 3.11.4 (compared to 238 commits between 3.10.4 and 3.10.5). Among those, there is a fix for CVE-2023-41105 <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-41105>which affected Python 3.11.0 - 3.11.4. See gh-106242 <https://github.com/python/cpython/issues/106242> for details. There are also some fixes for crashes, check out the change log <https://docs.python.org/release/3.11.5/whatsnew/changelog.html> to see all information. Most importantly, the release notes on the downloads page <https://www.python.org/downloads/release/python-3115/> include a description of the Larmor precession. I understood some of the words there! <https://discuss.python.org/t/python-3-11-5-3-10-13-3-9-18-and-3-8-18-is-now…>Python 3.10.13 Get it here: https://www.python.org/downloads/release/python-31013/ 16 commits. <https://discuss.python.org/t/python-3-11-5-3-10-13-3-9-18-and-3-8-18-is-now…>Python 3.9.18 Get it here: https://www.python.org/downloads/release/python-3918/ 11 commits. <https://discuss.python.org/t/python-3-11-5-3-10-13-3-9-18-and-3-8-18-is-now…>Python 3.8.18 Get it here: https://www.python.org/downloads/release/python-3818/ 9 commits. <https://discuss.python.org/t/python-3-11-5-3-10-13-3-9-18-and-3-8-18-is-now…>Stay safe and upgrade! Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organization contributions to the Python Software Foundation. -- Łukasz Langa @ambv <https://discuss.python.org/u/ambv> on behalf of your friendly release team, Ned Deily @nad <https://discuss.python.org/u/nad> Steve Dower @steve.dower <https://discuss.python.org/u/steve.dower> Pablo Galindo Salgado @pablogsal <https://discuss.python.org/u/pablogsal> Łukasz Langa @ambv <https://discuss.python.org/u/ambv> Thomas Wouters @thomas <https://discuss.python.org/u/thomas>

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Collecting unassigned Expressions
by Guenther Sohler Aug. 24, 2023

Aug. 24, 2023

Hi I am wondering If an embedded Python Interpreter can detect unassigned Expressions. Cases where functions Return values but they are Not assignwd. E.g. Calc_square(4) Or 3*4-myval() Thank you for your hints

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