Unicode & Character Encodings in Python: A Painless Guide

Handling character encodings in Python or any other language can at times seem painful. Places such as Stack Overflow have thousands of questions stemming from confusion over exceptions like UnicodeDecodeError and UnicodeEncodeError. This tutorial is designed to clear the Exception fog and illustrate that working with text and binary data in Python 3 can be a smooth experience. Python’s Unicode support is strong and robust, but it takes some time to master.

This tutorial is different because it’s not language-agnostic but instead deliberately Python-centric. You’ll still get a language-agnostic primer, but you’ll then dive into illustrations in Python, with text-heavy paragraphs kept to a minimum. You’ll see how to use concepts of character encodings in live Python code.

https://realpython.com/python-encodings-guide/

Python at Netflix

As many of us prepare to go to PyCon, we wanted to share a sampling of how Python is used at Netflix. We use Python through the full content lifecycle, from deciding which content to fund all the way to operating the CDN that serves the final video to 148 million members. We use and contribute to many open-source Python packages, some of which are mentioned below. 

https://medium.com/netflix-techblog/python-at-netflix-bba45dae649e

PySnooper – Never use print for debugging again

PySnooper is a poor man’s debugger.

You’re trying to figure out why your Python code isn’t doing what you think it should be doing. You’d love to use a full-fledged debugger with breakpoints and watches, but you can’t be bothered to set one up right now.

You want to know which lines are running and which aren’t, and what the values of the local variables are.

Most people would use print lines, in strategic locations, some of them showing the values of variables.

PySnooper lets you do the same, except instead of carefully crafting the right print lines, you just add one decorator line to the function you’re interested in. You’ll get a play-by-play log of your function, including which lines ran and when, and exactly when local variables were changed.

What makes PySnooper stand out from all other code intelligence tools? You can use it in your shitty, sprawling enterprise codebase without having to do any setup. Just slap the decorator on, as shown below, and redirect the output to a dedicated log file by specifying its path as the first argument.

https://github.com/cool-RR/pysnooper

Python for NLP: Introduction to the TextBlob Library

This is the seventh article in my series of articles on Python for NLP. In my previous article, I explained how to perform topic modeling using Latent Dirichlet Allocation and Non-Negative Matrix factorization. We used the Scikit-Learn library to perform topic modeling.

In this article, we will explore TextBlob, which is another extremely powerful NLP library for Python. TextBlob is built upon NLTK and provides an easy to use interface to the NLTK library. We will see how TextBlob can be used to perform a variety of NLP tasks ranging from parts-of-speech tagging to sentiment analysis, and language translation to text classification.

https://stackabuse.com/python-for-nlp-introduction-to-the-textblob-library/

How to build a serverless clone of Imgur using Amazon Rekognition and DynamoDB

In a previous article, we managed to build a very simple and somewhat primitive Imgur clone — using Amazon Cognito for registration and login before uploading images to the site for all to see.

Now, it had a few issues and these must be addressed before we go on to any funding rounds. We don’t want to scare away any potential investors with a few teething issues.

The issues preventing funding

Let’s go through the issues that need to be resolved prior to a round of Series A funding from any potential investors.

  1. In order to render the home page, it would hit the s3 bucket storing all of these images and then return them as a big JSON list. No pagination, no smaller images. If this thing is going to scale in any real sense then this will have to be addressed. We will have to introduce a database and proper pagination of results.
  2. It doesn’t really do anything “cool”. In order to address this, I thought I’d play around with AWS Rekognition and see if we could add some machine learning image recognition to the site. We can then browse images based on type should we so wish!
  3. There were a couple of frontend things that could have been improved upon, like for instance, you can’t click on an image to view just that one image by itself. We need to add a single page that will fetch the image location and its tags from a database. I won’t cover how I fixed this, but feel free to browse the code which I link to at the bottom of the article!

Once we have addressed these we should hopefully be in a far better place to attract big-money investors. Our finished product after we’re finished with our updates should look something like this:

Notice the tags — these were generated using Amazon Rekognition

https://read.acloud.guru/building-an-imgur-clone-part-2-image-rekognition-and-a-dynamodb-backend-abc9af300123

Writing a systemd Service in Python

Many Linux distributions use systemd to manage the system’s services (or daemons), for example to automatically start certain services in the correct order when the system boots.

Writing a systemd service in Python turns out to be easy, but the complexity of systemd can be daunting at first. This tutorial is intended to get you started.

When you feel lost or need the gritty details, head over to the systemd documentation, which is pretty extensive. However, the docs are distributed over several pages, and finding what you’re looking for isn’t always easy. A good place to look up a particular systemd detail is systemd.directives, which lists all the configuration options, command line parameters, etc., and links to their documentation.

Aside from this README.md file, this repository contains a basic implementation of a Python service consisting of a Python script (python_demo_service.py) and a systemd unit file (python_demo_service.service).

The systemd version we’re going to work with is 229, so if you’re using a different version (see systemctl --version) then check the systemd documentation for things that may differ.

https://github.com/torfsen/python-systemd-tutorial

HFT-like Trading Algorithm in 300 Lines of Code You Can Run Now

Commission Free API Trading Can Open Up Many Possibilities

Alpaca provides commission-free stock trading API for individual algo traders and developers, and now almost 1,000 people hang around in our community Slack talking about many different use cases. Among other things, like automated long-term value investing and Google Spreadsheet trading, high-frequency trading (“HFT”) often came up as a discussion topic among our users.

Is High-Frequency Trading (“HFT”) That Special?

Maybe because I don’t come from a finance background, I’ve wondered what’s so special about hedge funds and HFTs that those “Wallstreet” guys talk about. Since I am a developer who always looks for ways to make things work, I decided to do research and to figure out myself on how I could build similar things to what HFTs do.

I am fortunate to work with colleagues who used to build strategies and trade at HFTs, so I learned some basic know-how from them and went ahead to code a working example that trades somewhat like an HFT style (please note that my example does not act like the ultra-high speed professional trading algorithms that collocate with exchanges and fight for nanoseconds latency). Also, because this working example uses real-time data streaming, it can act as a good starting point for users who want to understand how to use real-time data streaming.

The code of this HFT-ish example algorithm is here, and you can immediately run it with your favorite stock symbol. Just clone the repository from GitHub, set the API key, and go!

https://medium.com/automation-generation/hft-like-trading-algorithm-in-300-lines-of-code-you-can-run-now-983bede4f13a