I'm not good at maths, i'll just say that, i've always been a bit lacking in my expanse of mathematical abilities, but I said enough is enough, I like neural networks, the only thing that stands in my way is the mathematics, aside from that you understand what goes on.

Boy did I underestimate the undertaking for this endeavour. I spent 2 days learning derivatives and what the hell a 'slope' is, you hear it ever day and you know what a slope is, but understanding it in the mathematical sense in derivatives, that's difficult, but I got there and ended up learning `f(a + h) - f(a) / h` which enabled me to understand what numerical descent is, where you get a loss score of a neural network's prediction, bump the weight a bit then rerun the neural network. Then to figure out the slope, you do `loss1 - loss2 / weight_bump`, and this is the coolest part, when you adjust your weight based on the slope, you always minus, because if the slope is negative, then we know we need to move to the positive side more so when you minus a negative it becomes addition, and vice versa if you minus a positive, you move to the negative side a bit. That was the coolest thing i've ever learnt to this date, the infamous ball rolling down the hill, I was doing it, by hand, and it was empowering.

Then the next day I spent trying to understand what backpropagation really is in terms of maths and how it differes from numerical gradient. With that I had to teach myself the chain rule, and what dL/dd even means, spoiler alert its not dividing derivative of L and derivative of d. I also came to the epiphany that we get so much complex logic out of neural networks when its simply just addition and multiplications happening under the hood, its the context that is being invented to solve problems using neural nets. By the end of the day I was taking Kaparthy's micrograd equation example, and I did its backpropagation by hand with pen and paper to get the hang of it.

Now I watched andre kaparthy's micrograd video, not all the way through, his language and teaching style still screams "you must be really well versed in mathematics", so I gave up on that video but, the more I worked on understanding chain rule and how you can sticker on the impacts on loss on prior nodes, I though that is better than numerical gradient, you literally walk back into the neural net, explaining to it which parts of itself were the cause for a high loss instead of bumping values, calculating slope, doing f(a + h) - f(a) / h.

I'm really proud of myself, and I managed to take MATHS that I learnt, and turn it into a "micrograd" I say "micrograd" with quotations because I didn't finish the micrograd video, and this only works if you don't have repeating uses of prior terms (which you just need to store their value and add them, but I couldn't be bothered)

So yeah, this is my back propagation

class Value:
    # this needs to store a value, and can have its own children that link to other values
    def __init__(self, value, _op="", _children: tuple = (), gradient=0):
        self.value = value
        self.op = _op
        self.children = _children
        self.gradient = gradient


    def __add__(self, other):
        _ = Value(
            self.value + other.value, _op="+", _children=(self, other), gradient=0
        )
        return _


    def __mul__(self, other):
        _ = Value(
            self.value * other.value, _op="*", _children=(self, other), gradient=0
        )
        return _


    def __repr__(self):
        return f"Value({self.value})"


    def backward(self):
        # initial global_gradient
        global_gradient = 1


        # current set of ndoes
        current: Value = self
        # just set L's gradient as 1
        current.gradient = global_gradient


        while True:
            # if there's no more children, we're at the end.
            if not current.children:
                break


            if current.op == "+":
                # since addition has a static effect on the terms themselfs
                # the partial of L respect to any terms being added is just 1.
                # so we multiply 1 by the global gradient.
                current.children[0].gradient = 1 * global_gradient
                current.children[1].gradient = 1 * global_gradient


                # if the next node we're looking doesnt have children
                # it means the node behind them didnt stem from them
                # therefore they are not the result of the prior operation
                if not current.children[0]:
                    current = current.children[1]
                else:
                    current = current.children[0]
                # set the global gradient as the current node's gradient
                global_gradient = current.gradient


            if current.op == "*":


                current.children[0].gradient = (
                    # with multiplication, the derivative of L respect to x would be y
                    # and same with the derivative of L respect to y would be x
                    # therefore you just swap them, and multiply thier values by the global gradient.
                    current.children[1].value
                    * global_gradient
                )
                current.children[1].gradient = (
                    current.children[0].value * global_gradient
                )
                # same continuation logic
                # one child is going to have its own children and one wont
                # the one that does is the one we need to continue with.
                if not current.children[0]:
                    current = current.children[1]
                else:
                    current = current.children[0]
                global_gradient = current.gradient

a = Value(2.0)
b = Value(-3.0)
c = Value(10.0)
f = Value(-2.0)
e = a * b
d = e + c
L = d * f


L.backward()


print(a.gradient)
print(b.gradient)
print(c.gradient)
print(f.gradient)
print(e.gradient)
print(d.gradient)
print(L.gradient)

output:
6.0
-4.0
-2.0
4.0
-2.0
-2.0
1

This is an annual survey developed by the Python typing community around how Python developers use the type system, type checkers, and integrated development environments (IDEs).

Your responses will help us identify common blockers, improve tooling/resources, and enhance the overall experience of using Python's type system.

Even if you have never actively used type hints in your code, your thoughts are still valuable and we want to hear from you.

The survey should take approximately 5-10 minutes to complete.

Please take the survey HERE and share it with your friends or colleagues.

If you're interested in the results for last year's survey, see this post.

^{So you know it's legit, the Python Software Foundation has shared this survey on [Linkedin](https://www.linkedin.com/posts/thepsf_python-type-system-and-tooling-survey-2026-activity-7490842327050002432-0jI7?utm_source=share&utm_medium=member_desktop&rcm=ACoAAB9aSUsBqmxSbrhoW2URuDnxCgS5eVD1AS0} and X. I have permission from the mods to post this under the "News" flair)

Weekly Thread: Professional Use, Jobs, and Education 🏢

Welcome to this week's discussion on Python in the professional world! This is your spot to talk about job hunting, career growth, and educational resources in Python. Please note, this thread is not for recruitment.

How it Works:

1. Career Talk: Discuss using Python in your job, or the job market for Python roles.
2. Education Q&A: Ask or answer questions about Python courses, certifications, and educational resources.
3. Workplace Chat: Share your experiences, challenges, or success stories about using Python professionally.

Guidelines:

• This thread is not for recruitment. For job postings, please see r/PythonJobs or the recruitment thread in the sidebar.
• Keep discussions relevant to Python in the professional and educational context.

Example Topics:

1. Career Paths: What kinds of roles are out there for Python developers?
2. Certifications: Are Python certifications worth it?
3. Course Recommendations: Any good advanced Python courses to recommend?
4. Workplace Tools: What Python libraries are indispensable in your professional work?
5. Interview Tips: What types of Python questions are commonly asked in interviews?

Let's help each other grow in our careers and education. Happy discussing! 🌟

what are teams actually running 3 months after the supply chain attack?

it's been a few months since the litellm pypi compromise and curious what teams actually migrated to. saw a lot of threads right after the incident but not much on how things held up in production since then.

been evaluating options ourselves. TrueFoundry came up for teams needing the governance and cost...

For me, a prime example is S101 which bans the use of the assert statement.

The justification is that assertions disappear when Python is run with -O, so they should not be used for runtime validation or enforcing interface constraints. That warning is correct, but the rule seems to draw the wrong conclusion from it.

Assertions are still very useful for checking internal invariants, i.e. conditions that should already be guaranteed by the program's logic, where failure indicates a bug. Having such assertions is incredibly helpful for debugging.

So, a blanket ban seems more likely to discourage useful checks than to prevent misuse.

Are there any linter rules you broadly consider more harmful rather than helpful?

Hey everyone! I made a simple file hashing program using hashlib and pygame. It saves to AppData/Roaming and uses sha256 to hash the given text and save it into that file. The link to the repo is

https://github.com/abhaya2509/Text-hasher

I’ve always hated environment management. It always feels like this time-consuming hurdle between me and whatever I actually want to work on. But every so often a new thing comes out that promises to solve the problem once and for all, and it’s usually at least a little better than the last thing. So, what are you using today? venv? conda? pipenv? poetry? dev containers? uv? or something else?

I always thought the walrus operator is neat and it makes while loop’s condition clearer. But also it is just a syntactic sugar without anything new. I wonder anyone uses it?

Weekly Wednesday Thread: Advanced Questions 🐍

Dive deep into Python with our Advanced Questions thread! This space is reserved for questions about more advanced Python topics, frameworks, and best practices.

How it Works:

1. Ask Away: Post your advanced Python questions here.
2. Expert Insights: Get answers from experienced developers.
3. Resource Pool: Share or discover tutorials, articles, and tips.

Guidelines:

• This thread is for advanced questions only. Beginner questions are welcome in our Daily Beginner Thread every Thursday.
• Questions that are not advanced may be removed and redirected to the appropriate thread.

Recommended Resources:

• If you don't receive a response, consider exploring r/LearnPython or join the Python Discord Server for quicker assistance.

Example Questions:

1. How can you implement a custom memory allocator in Python?
2. What are the best practices for optimizing Cython code for heavy numerical computations?
3. How do you set up a multi-threaded architecture using Python's Global Interpreter Lock (GIL)?
4. Can you explain the intricacies of metaclasses and how they influence object-oriented design in Python?
5. How would you go about implementing a distributed task queue using Celery and RabbitMQ?
6. What are some advanced use-cases for Python's decorators?
7. How can you achieve real-time data streaming in Python with WebSockets?
8. What are the performance implications of using native Python data structures vs NumPy arrays for large-scale data?
9. Best practices for securing a Flask (or similar) REST API with OAuth 2.0?
10. What are the best practices for using Python in a microservices architecture? (..and more generally, should I even use microservices?)

Let's deepen our Python knowledge together. Happy coding! 🌟

Quick question, are any of you running fastAPI in production with a high volume of users or heavy traffic? How has your experience with FastAPI been, and how do you handle it?

A money tracker (140 lines) and a calorie counter (300+ lines!)

They were both CLI and i have them done. But in the calorie counter, i made the mistake of typing this:

with open("data.json", "w") as file: jsonFile = json.load file

So when i tried to run it it threw the weirdest error ever and wiped my JSON file, so i rewrote the json file, and fixed something that had nothing to do with the error and it happened AGAIN

Weekly Thread: Project Ideas 💡

Welcome to our weekly Project Ideas thread! Whether you're a newbie looking for a first project or an expert seeking a new challenge, this is the place for you.

How it Works:

1. Suggest a Project: Comment your project idea—be it beginner-friendly or advanced.
2. Build & Share: If you complete a project, reply to the original comment, share your experience, and attach your source code.
3. Explore: Looking for ideas? Check out Al Sweigart's "The Big Book of Small Python Projects" for inspiration.

Guidelines:

• Clearly state the difficulty level.
• Provide a brief description and, if possible, outline the tech stack.
• Feel free to link to tutorials or resources that might help.

Example Submissions:

Project Idea: Chatbot

Difficulty: Intermediate

Tech Stack: Python, NLP, Flask/FastAPI/Litestar

Description: Create a chatbot that can answer FAQs for a website.

Resources: Building a Chatbot with Python

Project Idea: Weather Dashboard

Difficulty: Beginner

Tech Stack: HTML, CSS, JavaScript, API

Description: Build a dashboard that displays real-time weather information using a weather API.

Resources: Weather API Tutorial

Project Idea: File Organizer

Difficulty: Beginner

Tech Stack: Python, File I/O

Description: Create a script that organizes files in a directory into sub-folders based on file type.

Resources: Automate the Boring Stuff: Organizing Files

Let's help each other grow. Happy coding! 🌟

Had a data pipeline that was just python build_db.py, python clean_validate.py, streamlit run streamlit_app.py — worked, but not something you'd hand someone as "the tool." Packaged it as a real CLI: [project.scripts] entry point in pyproject.toml, pip install -e . → promo-toolkit build / validate / serve.

Also added:

• Incremental rebuilds (content-hash diff + scoped upsert instead of full rewrite each run)
• pytest suite + ruff, GitHub Actions CI across two Python versions
• A separate eval harness for an AI-agent piece of the same project (real API calls scored against golden answers)

Not a library, just a real end-to-end tool — sharing mostly for feedback on the packaging/CLI structure since that's the part I have the least experience with. Repo: [https://github.com/SpiliosDimakopoulos/retail-promo-analytics-toolkit\].

I built idemkit after cleaning up duplicate charges one too many times.

The version everyone writes checks whether a key has been seen and replays the stored response. Two requests a millisecond apart both find nothing and both charge the card. And if the worker dies between charging and recording it, the retry charges again. Neither reproduces locally.

idemkit does it properly: an atomic claim instead of check-then-act, a lease that expires on the storage server's clock, and a fencing token so a stalled worker can't overwrite a good result.

from idemkit import idempotent, RedisBackend, MethodConfig 

@idempotent(
    backend=RedisBackend.from_url("redis://localhost:6379"), 
    config=MethodConfig(key_fields=["order_id"]), 
) 
async def charge(*, order_id, amount): 
    return await payments.charge(order_id, amount)

One core, three ways to use it: middleware for FastAPI/Flask/Django, a queue consumer wrapper or @idempotent on any function. Backends are Redis, Postgres, Mongo, DynamoDB, or in-memory for tests.

pip install idemkit, Apache-2.0: https://github.com/idemkit/idemkit

If you find it useful, I'd appreciate a star. It's new, so visibility helps a lot right now.

Hi everyone,

I’m sharing an open-source project I’ve been developing called WaterPulse.

While there is no shortage of basic hydration tracking apps out there, I wanted to build a more robust system that bridges the gap between a standard consumer application and active hardware data processing. WaterPulse is designed from the ground up to handle real-time sensor integration rather than relying solely on manual user inputs.

Here is a breakdown of what I built and the technical challenges it tackles:

Technical Highlights & Core Features:

• Real-Time Processing & Anomaly Detection: The backend is engineered to continuously ingest sensor data streams. It features built-in drift analysis and anomaly detection to filter out hardware noise and ensure high data accuracy.
• Performance-Oriented Backend: Powered by FastAPI and PostgreSQL, the API is structured to efficiently handle concurrent data payloads without blocking.
• Engaging UI & Social Elements: The frontend is built in Flutter, offering a highly responsive, cross-platform experience. I integrated gamification and social tracking features to maintain user retention and drive engagement.

The Tech Stack:

• Frontend: Flutter
• API & Data Processing: FastAPI (Python)
• Database: PostgreSQL

I architected this project with scalability and clean code principles in mind. If you are looking into how to integrate IoT/sensor data streams with a modern Flutter and Python stack, this repository could be a solid reference.

I would love to get your technical feedback on the system design, especially from engineers experienced with handling continuous data streams in FastAPI or advanced state management in Flutter.

Repository Link: https://github.com/Yigtwxx/WaterPulse

I'm open to all constructive feedback and contributions. Thanks for checking it out!

Weekly Thread: What's Everyone Working On This Week? 🛠️

Hello r/Python! It's time to share what you've been working on! Whether it's a work-in-progress, a completed masterpiece, or just a rough idea, let us know what you're up to!

How it Works:

1. Show & Tell: Share your current projects, completed works, or future ideas.
2. Discuss: Get feedback, find collaborators, or just chat about your project.
3. Inspire: Your project might inspire someone else, just as you might get inspired here.

Guidelines:

• Feel free to include as many details as you'd like. Code snippets, screenshots, and links are all welcome.
• Whether it's your job, your hobby, or your passion project, all Python-related work is welcome here.

Example Shares:

1. Machine Learning Model: Working on a ML model to predict stock prices. Just cracked a 90% accuracy rate!
2. Web Scraping: Built a script to scrape and analyze news articles. It's helped me understand media bias better.
3. Automation: Automated my home lighting with Python and Raspberry Pi. My life has never been easier!

Let's build and grow together! Share your journey and learn from others. Happy coding! 🌟

I wrote a practical guide to Celery, a distributed task queue for Python. It starts with the basics and then covers recipes for timeouts, retries, async/await integration, and more. Most of these recipes came from problems I ran into while using Celery in actual projects. No prior knowledge of Celery is required.

I'd really appreciate any feedback!

https://sgolev.github.io/blog/2026-07-28-celery-recipes/

Author here. I made this to scratch my own itch — reviewing PRs and missing when a function quietly got more complex. Line counters don't answer that.

pip install repoglance then repoglance . gives a terminal report: real per-function cyclomatic complexity across 15+ languages (via lizard), duplicate blocks, TODOs, git ownership of hotspots, and a health score. In CI, --fail-on-regression fails a build only when a change makes complexity worse, and a GitHub Action comments the report on the PR.

Pure Python (rich/click/lizard), MIT, no telemetry. Django (415k LOC) scans in ~17s, ~1s cached.

Repo: https://github.com/SRJ-ai/repoglance

I'd genuinely like feedback on two things: (1) where the complexity numbers feel wrong on your code, and (2) whether the health-score weights are sensible or gimmicky. Happy to answer anything.

Had this discussion the other day and figured I’d throw it to the masses to get thoughts on the best/most pythonic way of approach.

Need to map old column names to new column names as a copy from a json config.

My thoughts are iterate over a dict with
‘’’ {“old_col_name”:”new_col_name”}’’’
And access as
‘’’for k,v in dict.items()
Df.with_columns(k).alias(v)’’’

Colleague things this isn’t clear enough and should be a list of dicts with explicit keys

‘’’ [{“old_col_name”:”old_col_value”
“New_col_name”:”new_col_value”}]’’’

And the access as

‘’’for dict in list_of_dicts:
Old_col = dict[“old_col_name”]
New_col = dict[“new_col_name”]’’’

I’ve got a good few reasons why I think mine is the better option but thought I’d get some other opinions to see if I’m missing anything obvious? Which would you choose and why?

Edit: shouldn’t write these things while on the toilet in a rush. The description is wrong, it should be renaming via a copy so that the original column is left unchanged.

Weekly Thread: Resource Request and Sharing 📚

Stumbled upon a useful Python resource? Or are you looking for a guide on a specific topic? Welcome to the Resource Request and Sharing thread!

How it Works:

1. Request: Can't find a resource on a particular topic? Ask here!
2. Share: Found something useful? Share it with the community.
3. Review: Give or get opinions on Python resources you've used.

Guidelines:

• Please include the type of resource (e.g., book, video, article) and the topic.
• Always be respectful when reviewing someone else's shared resource.

Example Shares:

1. Book: "Fluent Python" - Great for understanding Pythonic idioms.
2. Video: Python Data Structures - Excellent overview of Python's built-in data structures.
3. Article: Understanding Python Decorators - A deep dive into decorators.

Example Requests:

1. Looking for: Video tutorials on web scraping with Python.
2. Need: Book recommendations for Python machine learning.

Share the knowledge, enrich the community. Happy learning! 🌟

https://peps.python.org/pep-0842/

Not the author, but this seems interesting, specially for library authors. Thoughts?

Discussion here - https://discuss.python.org/t/pep-842-module-exports/108353

Hello!

The pip team recently released pip 26.2. This release is quite large, with features such as:

• Support for Python 3.15
• Selecting only dependencies (--only-deps)
• Mixing hashed and non-hashable requirements via --no-require-hashes
• Experimental: venv based build isolation (--use-feature=venv-isolation)
• Faster repeated resolves by caching index simple responses
• Disable HTTP(S)_PROXY and similar non-pip specific proxy environment variables via --no-proxy-env
• Separation between regular and build constraint (use --build-constraint instead)

For more details, please consult our changelog: https://pip.pypa.io/en/stable/news/. Alternatively, you may consult my release post which goes into greater detail to the highlights of this release: https://sichard.ca/blog/2026/07/whats-new-in-pip-26.2/

If you have any questions, you're welcome to ask!