Questions tagged [python-3.x]
Python 3 is the latest version of the Python programming language and was formally released on December 3rd, 2008.
156 questions
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Why did Python designers decide not to declare vars? [closed]
In Python when you want a local variable, you just assign to it x = 10.
In most modern languages you declare local vars (regardless of type):
JavaScript: let/const/var
Swift: let/var
Kotlin: val/var
...
- 235
-3
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2
answers
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Is it better practice to set default values for optional argparse arguments?
I mention python's argparse as an example but this would apply to any CLI argument parser library for any language. Just generally speaking, at a high level, if there are a lot of optional arguments ...
- 109
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3
answers
626
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Python logging in shared functions called by multiple main programs
I have reviewed this, but it doesn't seem to address what I'm asking here.
https://stackoverflow.com/questions/15727420/using-logging-in-multiple-modules
I want to have multiple programs call the same ...
- 133
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0
answers
65
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How can I use django to render a rotating view of a database?
As a toy problem for learning Django, I am trying to create a simple web app that tracks encounters and initiative for one of my D&D campaigns. I have a database with models for combatants:
class ...
2
votes
3
answers
457
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Does it make sense for an API with 1 daily job to do to be asynchronous?
This is a conceptual question about whether my specific use-case warrants the use of an asynchronous API.
Language: Python 3.11
Framework: FastAPI (ASGI)
I believe I am confused about what an ...
- 53
0
votes
2
answers
360
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Appropriate design pattern for providing a default Argparse instance, eliminating boilerplate
I'm using argparse.ArgumentParser extensively; however, it comes with a lot of boilerplate to set up, and this is especially noticeable when you've got more than a few common arguments that probably ...
- 19
0
votes
1
answer
232
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Match making algorithm respecting players' choices
I am currently developing an application in Python that has a match making functionality to form sports teams of 4 and group them by skill. The following has been implemented and works.
E.g.
Form ...
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0
answers
95
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What is the best way to implement the following type of paradigm?
I have the following piece of code. Line 1 is a container (for simplicity, one can think of it as a list of elements e1, e2, ..., en). Now there is a function function_fun which takes as input an ...
- 19
2
votes
2
answers
170
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OOP Best practices: Is there any reason to separate out Factory functionality from an abstract base class?
Consider the following python3 code:
from abc import ABC, abstractmethod
class Food(ABC):
_food_factory_map = {}
_recipes = {}
@classmethod
def getFood(cls, foodName):
return ...
- 29
1
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2
answers
1k
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Should I duplicate or inherit a python dataclass which changes attributes based on the version of an API endpoint?
I'm working on a python library for a REST API.I'm using python data classes to represent the structure of the returned JSON
The v2 of this API returns a slightly different object when compared to v1.
...
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0
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1k
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Python - Where do I store data classes which are common across different files?
I'm working on a python wrapper for a REST API. I'm using python data classes to store the shape of the JSON response of each endpoint so developers have features like autocomplete and objects they ...
- 127
21
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6
answers
7k
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Does subclassing int to forbid negative integers break Liskov Substitution Principle?
In Python 3, I subclassed int to forbid the creation of negative integers:
class PositiveInteger(int):
def __new__(cls, value):
if value <= 0:
raise ValueError("value ...
- 321
-2
votes
1
answer
91
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python language construct or facility to tag entering and exiting a while loop
Here's what I want to achieve:
while complex_compound_condition_statement:
foobar() # ... do some stuff
I would like the log output of the above to be:
<timestamp> INFO: started doing stuff ...
- 151
2
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1
answer
4k
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How to add some data to an Enum in Python
I have a class that I use to define different types of plots I am performing
class MyPlots(Enum):
STANDARDSCALE = "standard"
LOGSCALE = "log"
there are default values ...
- 39
5
votes
1
answer
365
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Does my View Model violate the Single Responsibility Principle? Or am I just used to toy examples from tutorials?
I am a very beginner writing one of my first webapps. I'm using FastAPI and I'm stuck on the logic of creating an endpoint that has to do a lot of things before it returns something back to the user. ...
- 159
-1
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1
answer
2k
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Are there different ways in Python to decorate class methods that dynamically assign themselves to a dict within the class?
Here's what I'd like to do in the form of working code, since it's difficult for me to explain otherwise:
from typing import Callable, Generic, TypeVar
from typing_extensions import Self
# The type ...
2
votes
2
answers
334
views
What is the best way to compartmentalize complex logic problems?
I am working on a problem with lots of if-then-else calculations. I am trying to compartmentalize the logic to make it more maintainable and less error prone. But, as I try options, I don't see what ...
- 139
0
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3
answers
3k
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Python best practice when logging optional arguments
I have a method that accepts one or more optional arguments and I'd like to log them, following the best practice of lazy interpolation of log values:
def frobnicate(a: str, b: int, c: typing.Optional[...
- 109
4
votes
2
answers
2k
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Should similar standalone functions go in a class?
I'm working to create a library in python that myself and a few colleagues will use. I'm struggling to conceptually understand how to best organize some code that feels like it doesn't cleanly fit ...
user400809
-4
votes
1
answer
93
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How to use DRY methods with OS commands with Python and classes
My goal is to learn more about OOP patterns and use DRY principles. I am trying this for wrapping an os command that interacts with a database using classes:
This works fine:
import subprocess
class ...
- 91
13
votes
6
answers
12k
views
Is it reasonable to use dictionaries instead of arguments?
In python I often see functions with a lot of arguments. For example:
def translate(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p):
// some code
return(x, y, z)
I like this pattern in some ...
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2
votes
1
answer
4k
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Type-hinting and accessing values that are not initialized in __init__ (Python)
Suppose I have an instance attribute that I don't initialize in __init__, but in normal use it should be initialized before any other methods use the value. I want to structure everything so that it ...
- 139
0
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0
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55
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Sync image files from network with mariadb-Database
i have as a mechanical engineering student in my practice semester to create a database that includes about 100k+ paths to images in our network. Every, lets say week, i have to synchronize all ...
- 1
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8
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7k
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Is using lambdas to express intent not pythonic?
PEP 8 states the following about using anonymous functions (lambdas)
Always use a def statement instead of an assignment statement that
binds a lambda expression directly to an identifier:
# Correct: ...
- 351
0
votes
1
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129
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designing high throughout system for storing hundred thousands incoming records per second in SQL server database
In our company we have a requirement where we would like to store hundred thousands incoming records per seconds. we currently a pub-sub model for processing many records(100/sec) from many system(~...
- 107
1
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1
answer
177
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legacy refactor and churn
I am trying to work on finding the following metrics
New Work - totally new code which does not replace other code.
Churn - code that is rewritten or deleted after being written
Help Others - where ...
- 141
1
vote
3
answers
6k
views
"Hard coded" vs. configuration files for values in libraries? (code organization question)
I'm trying to get a good understanding as to whether there is a best practice or standard regarding keeping values within your code libraries or referencing them from another config file. I don't ...
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1
answer
94
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In a language interpreted line by line - is optimizing similar lines of code within a module into functions better in terms of efficiency? [duplicate]
While writing python code (I write python-selenium for GUI automation), I am facing situations wheer I have to deal with 5 widgets that do the same thing, just there xpath is differs by one term.
# ...
- 101
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1
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367
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How to design "define-by-run" API?
I am amazed by the way APIs of some machine learning packages are designed, namely Chainer's and Pytorch's "define-by-run" API. Even Optuna, a hyper parameter tuning library has "define-...
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vote
2
answers
5k
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Alternative to using regex in Python
Background
I do programming with Python and now and then i run into a situation where i have to use regex
Typically i try to learn a bit about it and look at examples of doing things similar to what i'...
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1
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2k
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Python generating payload and parsing payload
(Using python) I am looking to generate a bytes (or can be string that I convert to bytes) that is a message to send over TCP. The format is [Header][Length][Payload].
Within [Header] is a [...
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2
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Is a python `abstract property` that returns an abstract class an example of the Factory Pattern?
I need to document my design, in particular, the design patterns used, and would like to use the standard terminology.
From Refactoring Guru, "Factory Method defines a method, which should be ...
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2
answers
1k
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Python import order, mixing from ... import ... and import ... (and import ... as ...)
This is the mess of imports currently at the top of my file:
import argparse
from copy import deepcopy
from functools import cmp_to_key, partial
from itertools import chain
import math
from ...
user224123
-1
votes
1
answer
2k
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Python dynamically import modules
I am trying to find the best practice for importing modules dynamically. I have multiple files in a specific folder called providers which contain a class Updater and all of them have the same objects....
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1
answer
1k
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Reading txt file till certain point and then create new txt file out of existing file
I have a txt file from where I want to create new files based on the data which is up to '$'character.
My input file looks like:
string1
string2
string3
$string4
string5
$string6
string7
... (and so ...
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1
answer
3k
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Test to check that executing a function does not raise an exception
I have the following function:
def create_dic():
key_list = ['a','b']
val_list = [1, 2]
dic = {}
for i in range(2):
dic[key_list[i]] = val_list[i]
return dic
I ...
- 113
1
vote
1
answer
188
views
How to deploy python microservices app updates?
I'm working on python microservices based app and I'm wondering how to ship updates.
Let's start by a summary of what I have:
Code base on git (several repos)
The app is running on several remote ...
- 13
0
votes
1
answer
205
views
Class Design question concerning adding a new "DRAFT" state to an object
We have some entities in our code:
-"View" and View has some attributes and also contains one or many "SubViews"
-And each "SubView" has some attributes and contains one or more "Tweet" entities.
...
- 109
-4
votes
1
answer
150
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Best practices when interfacing Python and C code
I have a piece of code that I developed in an academic context for which I would like to build a nice frontend. My approach to coding has been very academic to this point (read: I made stuff up as I ...
- 115
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0
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207
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Combine/Sync Amazon S3 and MongoDB Atlas with Elastic Search
I have many continuously growing (through scrapping) collections in MongoDB Atlas. The documents in each collection follows the following schema:
{
"source_url": "<some url on the web>",
"html":...
- 111
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1
answer
142
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Finding the domain(s) of variables in a Linear Program using the constraints? (Constraint programming/Linear programming)
Forgive my jargon , as I'm not very familiar with Constraint Satisfaction Problem(s) or Linear Programming procedures (For eg: Presolve)
I have very trivial constraint set from variables of ...
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1
answer
418
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Is Python's Django WebFramework good to design Expert System as a Web App?
I hope everyone is good. Well, I am at the end of my degree BS (Software Engineering), and in the third Phase of my Final Year Project named as 'Test Phase'.
My Project is to build an Expert System ...
- 173
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1
answer
247
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Proper program structuring in Python
So, recently I have been doing a lot of programming in Python.
I have noticed that my programs can be somewhat hard to read. I usually have one main class which does everything, sort of like this:
...
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2
votes
1
answer
367
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Event Handling in Pygame
I am working on setting up a game in pygame and I've noticed that there isn't really a lot available for event handling. Basically, pygame has a queue of events that you can pull and iterate through ...
- 123
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3
answers
612
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Birthday Paradox, Analytical and Monte Carlo solutions give two systemically slightly different results [closed]
I was doing a Monte Carlo implementation of the Birthday Paradox in Python and I wanted to check if the results where the same as in the analytical implementation of the same problem (As they should ...
4
votes
2
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7k
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Python subclassed methods with additional arguments
Given the following structure where I want a method with a common name for each class, but each derived class needs an additional piece of information in order to form the appropriate result. ...
- 157
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1
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174
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How to expose multiprocessing python application to support invocation from command line and web
I have a python forecasting application that, for a given Entity, executes a fbprophet model multiple times varying the hyperparameters for each execution while tracking the best fit across the runs. ...
- 101
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2
answers
2k
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What is the difference between unit testing and handling exceptions
I have spent two full days now trying to understand the difference between unit testing and handling exception, but I can't get it.
Things I have understood (or I think I have):
Unit testing tests ...
- 139
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0
answers
127
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How to design realtime deeplearning based application for robotics using python?
I have created a machine learning software that detects objects(duh!), processes the objects based on some computer vision parameters and then triggers some hardware that puts the object in the ...
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1
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431
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Upload fingerprint from android/ios to cloud
I am working on a project to use fingerprint to authenticate the user. I don't want the authentication to be device specific. Hence want to upload the user fingerprint to cloud.
I do understand that ...
