teleren/devto huggingface dataset:
Unveiling Joint Variability: Exploring Covariance
Tags: python, datascience, programming
Published: 2023-12-13 01:50:33

In the realm of statistics, covariance serves as a powerful measure, offering insights into the joint variability between two variables. Understanding covariance is crucial, especially when analyzing relationships between financial instruments or variables. In this blog post, we'll embark on a journey to explore covariance, practice calculating it, and unravel its implications in the world of data analysis.

## Covariance: A Measure of Joint Variability

Covariance assesses how much two variables change together. It can take positive or negative values, indicating the direction of the relationship between the variables:

- **Positive Covariance:** The variables tend to increase or decrease together.
- **Negative Covariance:** One variable tends to increase when the other decreases.


## Interpreting Covariance

- **Positive Covariance:**
  - Indicates a tendency for the two variables to move in the same direction.
  - A large positive covariance suggests a strong positive relationship.

- **Negative Covariance:**
  - Indicates a tendency for one variable to increase when the other decreases.
  - A large negative covariance suggests a strong negative relationship.

- **Covariance Near Zero:**
  - Implies little to no linear relationship between the variables.

## Calculating Covariance in Python

```python
# Python code for calculating covariance
import numpy as np

# Example data
data_X = np.array([1, 2, 3, 4, 5])
data_Y = np.array([5, 4, 3, 2, 1])

# Calculate covariance
covariance = np.cov(data_X, data_Y)[0, 1]

print(f"Covariance: {covariance}")
```

In this example, we use NumPy's `cov` function to calculate the covariance between two arrays, `data_X` and `data_Y`.

## Covariance Matrix

Covariance can also be represented in a matrix form when dealing with multiple variables. The covariance matrix provides a comprehensive view of the relationships between all pairs of variables.

```python
# Python code for calculating covariance matrix
import numpy as np

# Example data with multiple variables
data = np.array([[1, 2, 3, 4, 5],
                 [5, 4, 3, 2, 1],
                 [2, 3, 4, 5, 6]])

# Calculate covariance matrix
covariance_matrix = np.cov(data)

print("Covariance Matrix:")
print(covariance_matrix)
```

## Conclusion

Covariance is a fundamental concept in statistics, offering valuable insights into the joint variability between two variables. In the financial world, understanding covariance is pivotal for assessing the relationships between different financial instruments and making informed investment decisions. As you delve into data analysis and explore the intricate relationships within your datasets, covariance becomes a powerful tool in your analytical toolkit. Happy exploring!
The unlikely adventure in Ecuador
Published: 2023-12-13 01:49:08

# A Husky's Job Offer

Picture this: I'm in San Salvador, wrapping up my last two weeks in the capital, where I've become a temporary kickboxing apprentice. As I'm practicing my roundhouse kicks and trying to perfect my uppercut, I find solace in the company of my newfound friend, Galo—the husky, who was my roommate in the AirBnB I was renting.

One day, after a cheesy set of pupusas for breakfast, I check my inbox. Amidst the usual slew of sustainability newsletters [Work on climate](workonclimate.org), [Climatebase.org](Climatebase.org) and spam from Figma sheets, there it is—an email from a certain Galo Arboleda. The subject line reads, "Teaching Opportunity in Quito!"

I squint at the screen, wondering if my post-workout annoying pain in my shins is playing tricks on me. Galo Arboleda, the Academic Director of the South American Language Centre in Quito, has somehow discovered my existence through my workaway account which was once created during a caffeine-fueled bout of wanderlust.

The email goes on to explain that they're in dire need of an English conversationalist in Quito, and my profile, unbeknownst to me, has the perfect blend of linguistic prowess and nomadic charm. Galo, the husky, tilts his head, as if sensing the gravity of the situation unraveling in my own crane.

"Could this be it?" I wonder aloud, half expecting Galo the husky to respond with a bark of approval. Instead, he gives me a nonchalant look, clearly unimpressed by the sudden turn of events.

As I consider the possibilities—teaching English in the vibrant city of Quito, surrounded by the majestic Andes—I realize that sometimes, life's most unexpected invitations come from the most unexpected sources. So, with Galo the husky's lazy nod of approval, I decide to pack my bags, bid farewell to my good-ol' friend Massimo Formby, and embark on a new chapter of my nomadic journey.

Little did I know that this whimsical invitation from Galo would become a tale to chuckle about whenever someone asks, "How did you end up in Quito, anyway?"
MATLAB: FITS file -keyword
Tags: matlab, cheatsheet
Published: 2023-12-13 01:45:23

| - | - |
| --- | --- |
| [readCard](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readcard.html) | Header record of keywords |
| [readKey](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkey.html) | Keyword |
| [readKeyCmplx](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkeycmplx.html) | A keyword in the form of a complex scalar value |
| [readKeyDbl](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkeydbl.html) | Keyword in the form of double precision value |
| [readKeyLongLong](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkeylonglong.html) | Keyword in the form of `int64` |
| [readKeyLongStr](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkeylongstr.html) | long string value |
| [readKeyUnit](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readkeyunit.html) | The physical unit string in the key |
| [readRecord](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.readrecord.html) | Header record specified by number |
| [writeComment](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.writecomment.html) | Write or append COMMENT keyword to CHU |
| [writeDate](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.writedate.html) | Write DATE keyword to CHU |
| [writeKey](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.writekey.html) | Update or add new keywords to the current HDU |
| [writeKeyUnit](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.writekeyunit.html) | write physical unit string |
| [writeHistory](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.writehistory.html) | Write or append HISTORY keyword to CHU |
| [deleteKey](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.deletekey.html) | Delete key by name |
| [deleteRecord](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.deleterecord.html) | Delete keywords by record number |
| [getHdrSpace](https://www.mathworks.com/help/matlab/ref/matlab.io.fits.gethdrspace.html) | The number of keywords in the header |

> ## Useful links
> - [Create Online cheatsheet](https://simplecheatsheet.com/)
> - [MATLAB Cheatsheet](https://simplecheatsheet.com/matlab)
A beginner of python
Tags: beginners, news
Published: 2023-12-13 01:32:44

Python is known for its simplicity and readability, which makes it great for beginners to learn. One fundamental concept in Python is the use of indentation for code blocks. In many programming languages, braces or keywords are used to define blocks of code, but in Python, indentation with spaces or tabs determines the structure of the code.

For example, let's look at a simple if statement:

anime advent calendar = 20
if anime advent calendar >= 18:
    print("These are anime advent calendar.")
else:
    print("These are not yet anime advent calendar.")

In this code snippet, notice how the lines of code after the if statement and the else statement are indented beneath them. The indentation creates the code block associated with each condition. It is important to maintain consistent indentation levels throughout your code to ensure that it runs correctly.

By using indentation, Python encourages developers to write clean and well-structured code, making it easier to read and understand. So remember, proper indentation is crucial in Python to define and organize your code blocks!

By the way,if you want to know more about [anime advent calendar](https://calendarbox.store/),welcome to visit my page.
Unfortunately, Conditional UI Testing in Cypress
Tags: testing, tutorial, cypress
Published: 2023-12-13 01:19:21

How can we design tests and rich custom command macros when we don't know what the state of the UI will be? Conditional testing is strongly advised against by the Cypress team, but sometimes you just gotta do it.

In my case, I needed to be able to delete two types of item from a list, one of which would throw a confirmation modal, and the other wouldn't. It's hard to predict which case you'll face for many tests, so we need some sort of conditional logic here.

Conditional UI testing is hard in any tool. I can't just simply issue a `cy.get()` for the modal here, because it may never exist. Instead I have to insert a hard wait and the read the entire page looking for some text that I know will be in the modal header.

```ts
cy.wait(200);
cy.get('body').then(($body) => {
  if ($body.text().includes("The string I'm looking for")) {
    // Click the confirmation, only if the modal appears
    cy.contains('button', 'OK').click();
  }
});
```

When modals do appear, they often don't even append to the DOM in a logical location. Many times, they appear at the bottom of the document, devoid of anything but styling, free from any helpful neighboring relationships. For this reason, it's often necessary to query the entire `<body>` to find what you're looking for.

Doing what I've shown here is painful, and should be avoided. If you do need to do it though, this method can work in a pinch.
Navigating Risk and Volatility: Understanding Standard Deviation and Variance
Published: 2023-12-13 01:17:28

# Navigating Risk and Volatility: Understanding Standard Deviation and Variance

In the world of statistics, measures of dispersion provide valuable insights into the spread or variability of a dataset. Two key players in this realm are standard deviation and variance. In this blog post, we'll embark on a journey to explore the significance of these measures, particularly in assessing risk and volatility in financial data.

## 1. **Standard Deviation: The Fluctuation Indicator**

Standard deviation is a measure of how spread out the values in a dataset are. It quantifies the amount of variation or dispersion from the mean.

```python
# Python code for calculating standard deviation
import numpy as np

data = [10, 15, 20, 25, 30]
std_dev = np.std(data)
print(f"Standard Deviation: {std_dev}")
```

### Insights:
- High standard deviation indicates high volatility.
- Low standard deviation implies less risk and more stability.

## 2. **Variance: The Square of Volatility**

Variance is the square of the standard deviation. It provides a measure of how much each number in a dataset differs from the mean.

```python
# Python code for calculating variance
variance = np.var(data)
print(f"Variance: {variance}")
```

### Insights:
- Variance is a reflection of the average squared deviation from the mean.
- Often used in mathematical contexts but not as intuitive as standard deviation.

## Risk and Volatility in Financial Data:

### Standard Deviation and Risk:

In finance, standard deviation is a key player in risk assessment. For a portfolio of investments, a higher standard deviation implies greater price variability, indicating higher risk. Investors often analyze the standard deviation of historical returns to gauge the potential risk associated with an investment.

### Variance and Volatility:

Variance is a critical component in understanding volatility in financial markets. Volatility measures the degree of variation in trading prices over time. In the context of options trading, volatility is a key factor in pricing options. Higher volatility increases the potential price swings, impacting option prices.

## Conclusion:

As we navigate the world of statistics, standard deviation and variance emerge as powerful tools for quantifying variability and assessing risk. In the realm of finance, these measures play a pivotal role in understanding market dynamics, guiding investment decisions, and pricing financial instruments. Whether you're analyzing stock prices, managing a portfolio, or pricing options, a solid grasp of standard deviation and variance empowers you to navigate the seas of risk and volatility with confidence. Happy exploring!
null !== undefined
Tags: javascript
Published: 2023-12-13 00:49:30



I have noticed that many developers struggle with the  appropriate use of "null" and "undefined" in JavaScript.

"Null" refers to the absence of any object value. It is primarily used when an object is not present.

`console.log(typeof null) // 'object'`

"Undefined" is used when something is not defined. If any attribute in an API is missing, it will be considered as "undefined".

```
let i;
console.error(typeof i) // undefined
```
**Note:** It is important to always compare attribute values with "undefined" when processing API responses.  

I will be posting tricks I have been using in my journey.

So follow me on [LinkedIn](https://www.linkedin.com/mynetwork/discovery-see-all/?usecase=PEOPLE_FOLLOWS&followMember=mohdahshandanish).
Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO
Tags: games, checker, socket
Published: 2023-12-27 18:24:04

---
title: Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO
published: true
date: 2023-12-13 00:44:00 UTC
tags: Games,Checker,Socket
canonical_url: https://reactjsexample.com/multiplayer-checkers-game-made-with-phaserjs-reactjs-nestjs-socketio/
---

# checkers-multiplayer-game-phaser-nest
 ![Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO](https://reactjsexample.com/content/images/2023/12/Code_2023-12_20-39-07.jpg)

![Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO](https://camo.githubusercontent.com/8c8b9f7dc1892ca0131e00ba388811c9913425403551429494a0f755c9c7d20d/68747470733a2f2f692e696d6775722e636f6d2f6b4b48506657652e706e67) ![Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO](https://camo.githubusercontent.com/9c242f33a1413b5ee3002cc2b2ba78021195ccce05c68f38eb1b8a5bb92bdc71/68747470733a2f2f692e696d6775722e636f6d2f503464346e456a2e706e67)

Multiplayer Checkers game made with PhaserJS, React, NestJS, SocketIO (TypeScript). We guys did this for a bet company here in Brazil, but we got scammed and did not get paid, so we decided to turn it open source.

It’s incomplete in a lot of features for bet purpouses, but it’s primary gameplay is working nice with some know bugs that you can check in repository’s issues, all the gameplay rule features are server-authoritative and processed inside of it.

# Credits

Me – Main Developer

Jonatan (SkyAlpha) – [https://github.com/SkyAlpha](https://github.com/SkyAlpha) – [https://www.linkedin.com/in/jonatan-pietroski-60759585/](https://www.linkedin.com/in/jonatan-pietroski-60759585/) – Main Developer

Danilo (Dan) – [https://github.com/Dans1997](https://github.com/Dans1997) – Main Developer

[https://www.instagram.com/nieldsgn/](https://www.instagram.com/nieldsgn/) – Graphics Artist

[https://www.instagram.com/saporettidzn/](https://www.instagram.com/saporettidzn/) – Graphics Artist

[https://www.instagram.com/lpdamagica/](https://www.instagram.com/lpdamagica/) – Sound Designer

# Commercial Usage

Only code provided are free to use commercially under the respective license. All game artistic and sound/music resources are property of artists and not free to use commercially.

# Extra

![Multiplayer Checkers game made with PhaserJS, ReactJS, NestJS, SocketIO](https://camo.githubusercontent.com/4fde95cb3f284657be5f227bac1f7252988eeb4417c8b5113a0e15b8910026a9/68747470733a2f2f692e696d6775722e636f6d2f625750486e70632e706e67)

## GitHub

[View Github](https://github.com/ivopc/checkers-multiplayer-game-phaser-nest?ref=reactjsexample.com)
A feature-rich Google Drive clone with Next.js, Firebase, Stripe, and Clerk
Tags: googledocs, firebase, nextjs, stripe
Published: 2023-12-27 18:24:10

---
title: A feature-rich Google Drive clone with Next.js, Firebase, Stripe, and Clerk
published: true
date: 2023-12-13 00:43:00 UTC
tags: GoogleDocs,Firebase,Nextjs,Stripe
canonical_url: https://reactjsexample.com/a-feature-rich-google-drive-clone-with-next-js-firebase-stripe-and-clerk/
---

# NextJS Firebase Stripe Clerk – Google Drive Clone Project
 ![A feature-rich Google Drive clone with Next.js, Firebase, Stripe, and Clerk](https://reactjsexample.com/content/images/2023/12/Code_2023-12_20-38-15.jpg)

![A feature-rich Google Drive clone with Next.js, Firebase, Stripe, and Clerk](https://camo.githubusercontent.com/b2393c3e032ab15fca75b5c0ee4a74e50c7fa43353ad29b5b62512c6418202de/68747470733a2f2f6d656469612e67726170686173736574732e636f6d2f75316d49473638735436477a37397a684d75726e)

Embark on an exciting journey of building a Google Drive clone with the Next.js framework Firebase for backend functionality Stripe for payment integration and Clerk for authentication. This comprehensive course is designed for web developers eager to enhance their skills by creating a feature-rich cloud storage application that mirrors the functionality of Google Drive.

## 🚀 Demo

[https://drive.sammi.app](https://drive.sammi.app)

## 🧐 Features

Here’re some of the project’s best features:

- Stripe Integration
- Clerk Authentication
- Firebase Backend
- Light and Dark mode 🌓
- List rename delete drag & drop reorder and copy
- Stripe subscription for each organization to unlock unlimited boards
- Zustand state management
- Detail-oriented effects and animations using TailwindCSS
- Environment Typescript NextJS Setup

## 🛠️ Installation Steps:

1. Install packages

```
npm install & yarn install

```

2. Setup .env file

```
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=
CLERK_SECRET_KEY=
NEXT_PUBLIC_CLERK_SIGN_IN_URL=/sign-in
NEXT_PUBLIC_CLERK_SIGN_UP_URL=/sign-up
NEXT_PUBLIC_CLERK_AFTER_SIGN_IN_URL=/
NEXT_PUBLIC_CLERK_AFTER_SIGN_UP_URL=/
NEXT_PUBLIC_FIREBASE_API_KEY=
NEXT_PUBLIC_STRIPE_SECRET_KEY=
NEXT_PUBLIC_DOMAIN=

```

3. Start the app

```
npm run dev & yarn dev

```

## 💻 Built with

Technologies used in the project:

- ReactJS
- NextJS app routes
- NodeJS
- TailwindCSS
- ShadcnUI
- Clerk
- Stripe
- TypeScript

## GitHub

[View Github](https://github.com/samarbadriddin0v/google-drive-clone?ref=reactjsexample.com)
Discussão sobre o Advent of Code 2023 - Dia 6: Modelando problema com matemática
Tags: math, adventofcode, python, braziliandevs
Published: 2023-12-13 00:41:20

O problema do [dia 6 do Advent of Code desse ano](https://adventofcode.com/2023/day/6) pode ser resolvido usando matemática. Então resolvi testando o [SymPy](https://www.sympy.org/pt/) e ver o quanto ele facilita nas análises e contas. O resultado encontra-se no [seguinte notebook](https://github.com/eduardoklosowski/blog/blob/main/content/2023-12-12-advent-of-code-2023-dia-06/analise.ipynb).
Is New Tech Always Better?
Tags: newbie, beginners, hasanelsherbiny, discuss
Published: 2023-12-13 00:34:47

a few days ago ,I ran into a question asked by a junior developer which was 
"Are There Companies Still Using ASP.Net MVC Technology?"

the question was wondering if there some companies still using old/outdated technology while there is a newer version of this technology and the upgrade is not really hard.

but that question let me notice that people usually think the "New Tech" is equivalent to "Better Tech" , but is this really true?

let's walk through some new tech (at it's first release) and see if the new tech is always better or not?
for example "Silverlight" a product introduced by Microsoft as a replacement of adobe flash with a lot of promising features and improvements and a lot of propaganda about why this product will shape the future , but as you may know things didn't go this way

![Is New Tech Always Better?](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/levsglbgn9357wz0hjjo.gif)
the same criteria applies to tones of frontend frameworks and a lot of products introduced by google, apple Microsoft and many other big tech companies ,not only software products but hardware as well.
with the announcement of these products people start to talk about how amazing these products are and how fast they will jump into using them right after they are released, other may brag about using the latest technology in their projects as if this is the stamp of quality and advance. 

but why does this happen?
as i mentioned before with the announcement of a new product, there are a lot of propaganda and a lot of promises about the feature, for sure some of these promises are real and also some of these products are revolutionary and out of the box , that made people think if it's new for sure it's better.

in terms of software it's not correct to start using new tech immediately for some reasons

- new tech = new bugs/issues
- less community (because for sure community comes after popularity and real features not only promises)
- compatibility 
- upgrading costs 
  
and to answer the question I started with "Are There Companies Still Using ASP.Net MVC Technology?" 
yes there are for the reason mentioned earlier and also because it's not very outdated.