Last year the number of private investors at Moscow Stock Exchange (MOEX) has doubled and reached 3.86 million: about 1.9 million people have opened accounts at MOEX in 2019. The Saint Petersburg Stock Exchange which specializes in trading of foreign company shares has seen its accounts increase three times from 910,000 to 3,06 million over the past year.



This means that almost 2 million newbies without any actual trading experience and lacking any specialized software for trading/position analysis have entered the market.

Hello!

[UPD from 12.06.2021: if you're looking for a symbolic algebra library, AngouriMath is actively developed. It's on Github and has a website. Discord for questions]

Why does programming a calculator seem to be a task, which every beginner undertakes? History might have the answer — computers were created for this exact purpose. Unlike the beginners, we will develop a smart calculator, which, although won't reach the complexity of SymPy, will be able to perform such algebraic operations as differentiation, simplification, and equations solving, will have built-in latex support, and have implemented features such as compilation to speed up the computations.


Let's do it!

In order to get high quality production code, it's not enough just to ensure maximum coverage with tests. No doubts, great results require the main project code and tests to work efficiently together. Therefore, tests have to be paid as much attention as the main code. A decent test is a key success factor, as it will catch regression in production. Let's take a look at PVS-Studio static analyzer warnings to see the importance of the fact that errors in tests are no worse than the ones in production. Today's focus: Apache Hadoop.

After having discussed isolation problems and having made a digression regarding the low-level data structure, last time we explored row versions and observed how different operations changed tuple header fields.

Now we will look at how consistent data snapshots are obtained from tuples.

What is a data snapshot?

Data pages can physically contain several versions of the same row. But each transaction must see only one (or none) version of each row, so that all of them make up a consistent picture of the data (in the sense of ACID) as of a certain point in time.

Isolation in PosgreSQL is based on snapshots: each transaction works with its own data snapshot, which «contains» data that were committed before the moment the snapshot was created and does not «contain» data that were not committed by that moment yet. We've already seen that although the resulting isolation appears stricter than required by the standard, it still has anomalies.

RTSP is a simple signaling protocol which they cannot replace with anything for many years already, and it has to be admitted that they don't try really hard.

For example, we have an IP camera that supports RTSP. Anyone who has ever tested the traffic with a Sharkwire cable will tell you that first there comes DESCRIBE, then PLAY, and then the traffic begins to pour directly via RTP or wrapped in the TCP channel for instance.

Being a developer, I love to code especially in JavaScript. As per my experience, using reduce function is one of the toughest tasks in JS. Let me first elaborate on the Reduce concept!

In Wikipedia, it has many names viz.

Reduce
Fold
Accumulate
Aggregate
Compress

It is a function that folds a list into any data type. It's all about breaking a structure down into a single value. It's like folding a box! With reduce, you can turn an array [1,2,3,4,5] into the number 15 by adding them all up.

Popular cloud hosting DigitalOcean has recently launched its new marketplace selling preconfigured images that can help to quickly deploy an application server. It’s much like AWS, but DO is for those already using this provider’s services. Let’s see how to deploy a simple server for WebRTC streaming with a DO account for a $10/month fee based on Flashphoner WebCallServer and how such a server can be of use.

I've been talking about it for months, but in case you haven't heard, there's a new Windows Terminal in town. You can download it and start using it now from the Windows Store. It's free and open source.

At the time of this writing, Windows Terminal is around version 0.5. It's not officially released as a 1.0 so things are changing all the time.

Here's your todo - Have you installed the Windows Terminal before? Have you customize your profile.json file? If so, I want you to DELETE your profiles.json!

You’re utterly focused. You’ve lost track of time. Nothing else in the world exists. You’re living in the moment.

While this might sound like meditation, it’s a description that can also be applied to the state of flow – the feeling of being so engaged by your work, that you lose yourself to it completely, while massively increasing your productivity in the process.

It’s the holy grail that we all strive for, whether it’s a hobby we’re passionate about, or a project at work. Achieving our best and utilising our maximum potential at all times, can however, be a struggle.
We had the pleasure of talking with Dr. Jack Lewis, a neuroscientist with a passion for exploring how our minds work, to see what motivates us to do our best work, and the important roles that workplace environments, culture, and technology can play.


Have you thought about the influence of the nearest metro to the price of your flat? 
What about several kindergartens around your apartment? Are you ready to plunge in the world of geo-spatial data?





We are excited to announce updates to Model Builder and improvements in ML.NET. You can learn more in the «What’s new in ML.NET?.» session at .NET Conf.

ML.NET is an open-source and cross-platform machine learning framework (Windows, Linux, macOS) for .NET developers.

ML.NET offers Model Builder (a simple UI tool) and CLI to make it super easy to build custom ML Models using AutoML.

Using ML.NET, developers can leverage their existing tools and skillsets to develop and infuse custom AI into their applications by creating custom machine learning models for common scenarios like Sentiment Analysis, Recommendation, Image Classification and more!..

This week we issue a really huge selection of all the essential news you might have missed on Front-end development. Make sure to check the latest updates on CSS, HTML, and JavaScript.

Happy programmer's day! I wish you more bright commits, merged pull requests, less merge conflicts, and that your life branches remain relevant as long as possible. As a conceptual gift, I propose the implementation of a family tree by means of the Git version control system. Well… sounds like a plan!

For those who have immediately understood everything, I give links to the source code: GenealogyTreeInGit and family trees: mine and US presidents.

In addition, I implemented a simple social graph. It displays not only the degree of kinship, but also the status of relations between descendants, events such as wedding, divorce, childbirth, as well as contributions to the relations.

Why did I write this article?

When I was preparing for Java 8 OCA and OCP I found a lot of useful articles about subjects on Habr that helped me to choose the optimal path and save a considerable amount of time.

When I started preparing for OCA Oracle Database SQL (1Z0-071) I didn’t find any materials on Habr about this matter and found there to be limited information available on the Internet. Because of this I decided to write a complete guide in order to help others who are interested in this certification to help them save time and successfully pass what I consider to be a pretty hard exam.

In this article, I would like to propose an alternative to the traditional test design style using functional programming concepts in Scala. This approach was inspired by many months of pain from maintaining dozens of failing tests and a burning desire to make them more straightforward and more comprehensible.

Even though the code is in Scala, the proposed ideas are appropriate for developers and QA engineers who use languages supporting functional programming. You can find a Github link with the full solution and an example at the end of the article.

This week we issue a really huge selection of all the essential news you might have missed on Front-end development. Make sure to check the latest updates on CSS, HTML, and JavaScript.

This week we issue a really huge selection of all the essential news you might have missed on Front-end development. Make sure to check the latest updates on CSS, HTML, and JavaScript.

This week we issue a really huge selection of all the essential news you might have missed on Front-end development. Make sure to check the latest updates on CSS, HTML, and JavaScript.

Today at Xamarin Developer Summit, we announced XAML Hot Reload for Xamarin.Forms, which enables you to make changes to your XAML UI and see them reflected live, without requiring another build and deploy.

XAML Hot Reload for Xamarin.Forms speeds up your development and makes it easier to build, experiment, and iterate on your user interface. And this means that you no longer have to rebuild your app each time you tweak your UI – it instantly shows you your changes in your running app!

When your application is compiled using XAML Hot Reload, it works with all libraries and third-party controls. It will be available for iOS and Android in Visual Studio 2019 and Visual Studio 2019 for Mac. This works on all valid deployment targets, including simulators, emulators, and physical devices.

XAML Hot Reload will be available later in 2019, but you can sign up to to participate in the preview phase:

Sign Up for the Preview Now

GitHub hosts over 300 programming languages—from commonly used languages such as Python, Java, and Javascript to esoteric languages such as Befunge, only known to very small communities.


Figure 1: Top 10 programming languages hosted by GitHub by repository count 

One of the necessary challenges that GitHub faces is to be able to recognize these different languages. When some code is pushed to a repository, it’s important to recognize the type of code that was added for the purposes of search, security vulnerability alerting, and syntax highlighting—and to show the repository’s content distribution to users.

Linguist is the tool we currently use to detect coding languages at GitHub. Linguist a Ruby-based application that uses various strategies for language detection, leveraging naming conventions and file extensions and also taking into account Vim or Emacs modelines, as well as the content at the top of the file (shebang). Linguist handles language disambiguation via heuristics and, failing that, via a Naive Bayes classifier trained on a small sample of data. 

Although Linguist does a good job making file-level language predictions (84% accuracy), its performance declines considerably when files use unexpected naming conventions and, crucially, when a file extension is not provided. This renders Linguist unsuitable for content such as GitHub Gists or code snippets within README’s, issues, and pull requests.

In order to make language detection more robust and maintainable in the long run, we developed a machine learning classifier named OctoLingua based on an Artificial Neural Network (ANN) architecture which can handle language predictions in tricky scenarios. The current version of the model is able to make predictions for the top 50 languages hosted by GitHub and surpasses Linguist in accuracy and performance.