teleren/devto huggingface dataset:
Web Security Checklist ✔
Tags: webdev, javascript, tutorial
Published: 2020-10-15 08:36:31

---
title: Web Security Checklist ✔
published: true
description: For every full-stack application
tags: #webdev #javascript #tutorial
cover_image: https://dev-to-uploads.s3.amazonaws.com/i/wsxn9jztn671ymgwfbov.png
---
Howdy Dev Community! 🖐

Here you can find a list of all the most important security checks for your Web applications!

Not sure what all of these mean? 👉 Join [*Web Security experts mailing*](https://websecurity-academy.com/?utm_source=checklist_dev_to) to learn more as *every Tuesday* I send out a cool Web Security tip or trick! 💌 Also, I will send you a clickable PDF version of this checklist. ✔

Let's build secure apps! 🚀

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/2jmu6andfri1kqkltvne.png)

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/ld4j1pyilzdzvzes1k7s.png)
Formulas to Extract Unique Values In a Column in Excel-  A Simple Guide!!
Tags: excelformula, excelformulas
Published: 2020-10-15 12:04:40

---
title: Formulas to Extract Unique Values In a Column in Excel-  A Simple Guide!!
published: true
date: 2020-10-15 08:09:30 UTC
tags: ExcelFormula,Excelformulas
canonical_url: https://geekexcel.com/formulas-to-extract-unique-values-in-a-column-in-excel-a-simple-guide/
---

## Formulas to Extract Unique Values in a Column in Excel Office  365:

In this tutorial, we will explain how to Extract Unique Values in a Column with Formulas in Excel Office 365. Get an official version of **MS Excel** from the following link: [https://www.microsoft.com/en-in/microsoft-365/excel](https://www.microsoft.com/en-in/microsoft-365/excel)

## Formula Syntax:

- In Excel, for Extracting Unique Values from a Column, use the below formula.

**{=[IFERROR](https://geekexcel.com/use-iferror-function-in-microsoft-excel-365-easy-tutorial/)([INDEX](https://geekexcel.com/index-function-in-microsoft-excel-365-how-to-use/)($A$2:$A$10, [MATCH](https://geekexcel.com/how-to-use-match-function-in-microsoft-excel-365/)(0,INDEX(COUNTIF($B$1:B1,$A$2:$A$10)+(COUNTIF($A$2:$A$10)<>1),0,0),0)),””)}**

### Example:

- In the below screenshot, we entered the input range in **Column A**.
- Then, enter the given formula to get an output.
- After applying the formula, results will be displayed in a selected **Column B** as shown in the image.

![](https://eadn-wc04-371788.nxedge.io/cdn/wp-content/uploads/2020/07/op13.png)

## Syntax Explanations:

- **IFERROR** – In Excel, the IFERROR Function is used to display the custom result when the formula generates an error and it will show the standard results when no error detected. For more details about the [**IFERROR Function**](https://geekexcel.com/use-iferror-function-in-microsoft-excel-365-easy-tutorial/).
- **INDEX ** – The main purpose of the [**INDEX Function**](https://geekexcel.com/index-function-in-microsoft-excel-365-how-to-use/) is to get a value in a list or table based on the location.
- **MATCH** – This function will locate the position of a lookup value in a row, column, or table. Read more on the [**MATCH Function**](https://geekexcel.com/how-to-use-match-function-in-microsoft-excel-365/).
- **COUNTIF** – The Excel **COUNTIF Function** used to count cells in a range that matches a single condition or criteria. This function will perform partial matching in Logical operations and Wildcards.

## Closure:

In this short tutorial, we guided you to know the details about the **Formulas to Extract Unique Values in a Column in Excel Office 365**. If you have any suggestions, leave it in the below **comment** section. Thank you for visiting **[Geek Excel](https://geekexcel.com/)!!**
My experience with HacktoberFest 2020!
Tags: hacktoberfest
Published: 2020-10-15 08:08:39

## What I Learned From Hacktoberfest

<!-- What did you learn that can help others contribute to the project you worked on? What did you learn that can help the users of that project?! -->

This is the first I'm participating in an open-source contest and I just loved the feeling.

I submitted PRs to various repos by making sites performant, mobile responsive, etc. It really boosted my confidence!
MY EXPERIENCE WITH HACKTOBERFEST
Tags: hacktoberfest
Published: 2020-10-15 08:06:37

I GOT TO KNOW ABOUT HACKTOBERFEST FROM YOUTUBE ON 30 SEPTEMBER. IN EARLY MORNING I OPENED HACKTOBERFEST WEBSITE AND MADE 4 PULL REQUEST.
AFTER THAT I WAS WAITING FOR ABOUT 14 DAYS FOR MY PULL REQUESTS TO BE ACCEPTED.
FINALLY ON 15 OCTOBER IT GOT ACCEPTED.
I WAS VERY HAPPY WITH HACKTOBERFEST.
Hacktober Fest 2020
Tags: hacktoberfest
Published: 2020-10-15 08:05:46

## Hey! I successfully completed my hactoberfest challenge and it was a great learning & working experience for me.

<!-- What did you learn that can help others contribute to the project you worked on? What did you learn that can help the users of that project?! -->
Contributing to projects is a great way to improve your skills, gain confidence and practice coding. While finding the right project may take a bit of searching, it will be well worth your while.

Looking forward to get my hactober badge over my github :)
Github url:- https://github.com/mkaustubh
Formulas to Extract Unique Values Including First Duplicate in a Column!!
Tags: excelformula, excelformulas
Published: 2020-10-15 12:04:19

---
title: Formulas to Extract Unique Values Including First Duplicate in a Column!!
published: true
date: 2020-10-15 08:04:57 UTC
tags: ExcelFormula,Excelformulas
canonical_url: https://geekexcel.com/formulas-to-extract-unique-values-including-first-duplicate-in-a-column/
---

## Formulas to Extract Unique Values Including First Duplicate From An Excel Column:

In this tutorial, we explain the formulas to **Extract Unique**  **Values Including First Duplicate From an Excel Column**. Get an official version of **MS Excel** from the following link: [https://www.microsoft.com/en-in/microsoft-365/excel](https://www.microsoft.com/en-in/microsoft-365/excel)

## Formula Syntax:

- For extracting the unique values including the first duplicate from an Excel column, use the below formula.

**{=[IFERROR](https://geekexcel.com/use-iferror-function-in-microsoft-excel-365-easy-tutorial/)([INDEX](https://geekexcel.com/index-function-in-microsoft-excel-365-how-to-use/)($A$2:$A$10,[MATCH](https://geekexcel.com/how-to-use-match-function-in-microsoft-excel-365/)(0,COUNTIF($C$1:C1,$A$2:$10),0)),” “)}**

### Example:

- In the below screenshot, the input products are shown in **Column A**.
- Then enter the given formula as shown in the image to get unique values as output.
- After applying the formula, it will display the result in the selected **Column C** as shown below.

![](https://eadn-wc04-371788.nxedge.io/cdn/wp-content/uploads/2020/07/op9.png)

## Explanations for Syntax:

- **IFERROR** – This function will display the custom result when the formula generates an error otherwise it will show the standard result. Read more on the [**IFERROR Function**](https://geekexcel.com/use-iferror-function-in-microsoft-excel-365-easy-tutorial/).
- **INDEX** – The Excel INDEX Function is used to get a value in a list or table based on the location. Read more on the [**INDEX Function**](https://geekexcel.com/index-function-in-microsoft-excel-365-how-to-use/).
- **MATCH ** – In Excel, the main purpose of the MATCH Function is to locate the position of a lookup value in a row, column, or table. For more details on [**MATCH Function**](https://geekexcel.com/how-to-use-match-function-in-microsoft-excel-365/).
- **COUNTIF** – The **COUNTIF Function** count the cells in a range that matches a single condition or criteria and this function performs the partial matching in logical operations and Wildcards.

## Conclusion:

From this article, you can get the clarification about the **Formulas to Extract a Unique Values in a First Duplicate from an Excel Column**. Kindly drop your **feedback** in the comment section. Thank you for visiting **[Geek Excel](https://geekexcel.com/)!!**
Hacktoberfest2020(first time)
Tags: hacktoberfest
Published: 2020-10-15 08:02:51

## This experience was really great and I loved contributing
i guess open source contribution is one of the best ways to enhance your skills and learn, cauz you come to know what you need to learn and where you can contribute

<!-- This experience was really great and I loved contributing
i guess open source contribution is one of the best ways to enhance your skills and learn, cauz you come to know what you need to learn and where you can contribute -->
Elasticsearch Use Cases: Advanced Search Engine for Your Online Marketplace
Tags: onlinemarketplacedevelopment, advancedsearchengine, appdevelopment, integrations
Published: 2020-10-15 07:59:08

Discover Elasticsearch use cases. Learn about the advantages of Elasticsearch, its main features, and examples of its performance in online marketplaces.
[https://apiko.com/blog/elasticsearch-for-your-online-marketplace/](https://apiko.com/blog/elasticsearch-for-your-online-marketplace/)
Webhooks: Real-time notifications for blockchain events
Tags: blockchain
Published: 2020-10-15 07:57:17

Real-time webhook notifications for transactions and events
[Crypto APIs Webhooks](https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/eth/index#webhook-notifications) push notifications events have been already 1.5 years on the market, and recently we introduced Webhook 2.0 which adds massive optimization and better scalability.

[Crypto APIs](https://cryptoapis.io/) supports Webhooks (also called web callbacks or HTTP push APIs) to provide your applications with real-time information.

Many usage patterns require knowing when an event occurs: i.e., when a transaction is included in a block, or when an unconfirmed transaction is relayed through the network. Instead of requiring you to continuously poll resources, Crypto APIs provides push APIs to facilitate those use cases.

Crypto APIs supports [Webhook notifications](https://cryptoapis.io/blog/webhooks-push-notifications-for-blockchain-events/) for:

**Bitcoin, Ethereum, Litecoin, Bitcoin Cash, Ethereum Classic, DASH, DOGE, ERC20 tokens, Zilliqa, Ripple**

**Use cases**
Crypto exchanges, Wallets, Block explorers, Hardware ledgers and others can use Webhooks in the following matter:
1. Get updates when an event happens, no need for polling data all the time
2. Monitor incoming and outgoing transactions in any address
3. Get notification for new block, new transaction or new confirmation

**Webhook types**
To best understand how you can use the Webhook notifications, you should know what kind of events we support:

[NEW_BLOCK](https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-webhooks-create-new-block-webhook-endpoint) – Triggered for every new block added to the blockchain you’ve selected as your base resource.
[CONFIRMED_TX](https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-webhooks-create-confirmed-transaction-webhook-endpoint) – Triggered for every new transaction making it into a new block; in other words, for every first transaction confirmation.
[ADDRESS](https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-webhooks-create-address-transaction-webhook-endpoint) – Triggered any time an address appears in a transaction in a new block added to the blockchain or into the unconfirmed queue and waiting to be mined.
[TRANSACTION_CONFIRMATIONS](https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-webhooks-create-transaction-confirmations-webhook-endpoint) – Receive confirmations for a specified address.
First Experience of Open Source Contribution
Tags: hacktoberfest
Published: 2020-10-15 07:54:43

## What I Learned From Hacktoberfest

<!-- What did you learn that can help others contribute to the project you worked on? What did you learn that can help the users of that project?! -->
I get to know how the open source contribution works ,like forking repo, adding and merging code and generating pull requests .I contributed to various projects some of whose sole purpose was to share knowledge and skills about certain technology stack . 
Overall it was fascinating experience and I will try to contribute more to community now onwards .
The reverse of a number using python
Tags: python, softwareengineering, scripting, computerscience
Published: 2020-10-15 07:51:18

Given a number, reverse its digits and print the new number. 
     For example:
           Input : num = 8972
           Output: 2798

There are a couple of ways to solve this: 

<h1>1. Reverse Number using String slicing</h1>
We convert the given number to string using str() 
Reverse it using string slicing
Convert the reversed string to int and return the int.

```python
def reverseNumber(n):
    reversed_number = int(str(n)[::-1])
    return reversed_number
```


<h1> 2. Reverse Number using While Loop </h2>

Using a while loop, iterate through the list of the digits from the last one and append the digits into a new number.

```python
def reverseNumber(n):
    reversed_number = 0
    while(n!=0):
        r=int(n%10)
        reversed_number = reversed_number*10 + r
        n=int(n/10)                    
    return reversed_number
```
My first experience with Hacktoberfest and Open Source.
Tags: hacktoberfest, python, linux
Published: 2020-10-15 07:45:18

## What I Learned From Hacktoberfest

### Hacktoberfest is a very good platform which encourage young developers to contribute to open source and make a change in world.! 

### As a beginner I made a simple project for in which we have a TUI for Linux with Options to select which may help beginners in Linux. 

### Here is my GitHub Link for project 
### https://github.com/Creator-singh/linux-made-easy
MY First HACKTOBER2020
Tags: hacktoberfest, python, github, machinelearning
Published: 2020-10-15 07:37:25

## What I Learned From Hacktoberfest
![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/xggx34wednoym69bp5f1.jpg)

This is my first Hacktoberfest, I heard it from a friend of mine because we are both related to the computer science field, so we are already contributing to open-source as well as we are working on a Discord bot because This is his project and I am contributing to it. So I thought to take it to Hacktoberfest and participate in it. People can work on any project. Remember that it is not about any fest, it is all about contributing to the open-source community and Hacktoberfest is a great place because it not only recognizes your effort but also rewards you for it.
What I Learned From Hacktoberfest
Tags: hacktoberfest, python, cpp, beginners
Published: 2020-10-15 07:33:00

## What I Learned From Hacktoberfest

I think that the most important thing I learned from this year (is my first time) is that... Repo owners are humans.

Don't get me wrong I had develop for many people, but I think its was my second time pushing to a public repo and the first time it wasn't that humane as this time, mostly because of a really rush to get the issue I was fixing 😅.

The owners where polite, even one guy said that my code was the cleanest and legible he reviewed that day.

So the thing to take away from my post is...
Try it... you will find a kind enough repo to continue doing issues for them :heart:.

## Repos I pushed to:
{%github https://github.com/Python-World/Python_and_the_Web %}
{%github https://github.com/Abhishek627/Python %}
{%github https://github.com/amritansh22/Data-Structures-and-Algorithms-in-cpp %}
{%github https://github.com/collectivecloudperu/modo_oscuro_claro_mantener_modo_seleccionado %}
Latest Update on ETH2.0
Tags: blockchain, ethereum
Published: 2020-10-15 07:30:57

What’s New in Eth2?

https://hackmd.io/@benjaminion/eth2_news/https%3A%2F%2Fhackmd.io%2F%40benjaminion%2Fwnie2_201002
#ETHEREUM #developers #ETH #Blockchain #technology
What is clamp function in CSS?
Tags: css, html, webdev
Published: 2020-10-15 07:29:03

Hi everyone, today I going to explain the importance of an inbuilt CSS function called `clamp()` which can be used most of the time in building responsive web pages without the need of media queries.

### What is a clamp function?

The `clamp()` CSS function clamps a value between an upper and lower bound. clamp() enables selecting a middle value within a range of values between a defined minimum and maximum. 

While it’s a related idea to min() and max() it is different in specific ways:

- Order matters
- It only takes 3 parameters

- Those 3 parameters are

   1.The minimum

   2.The target value (ideally a relative unit)

   3.The maximum

- General syntax for clamp `clamp(MIN,VAL,MAX)`

- `clamp()` can be used for any of the following data types:
    - [`<length>`](https://developer.mozilla.org/en-US/docs/Web/CSS/length)
    - [`<frequency>`](https://developer.mozilla.org/en-US/docs/Web/CSS/frequency)
    - [`<angel>`](https://developer.mozilla.org/en-US/docs/Web/CSS/angle)
    - [`<time>`](https://developer.mozilla.org/en-US/docs/Web/CSS/time)
    - [`<percentage>`](https://developer.mozilla.org/en-US/docs/Web/CSS/percentage)
    - [`<number>`](https://developer.mozilla.org/en-US/docs/Web/CSS/number)
    - [`<integer>`](https://developer.mozilla.org/en-US/docs/Web/CSS/integer)


### Clamp function in action:

- Font size control using a `clamp()` with using a single media query

{% codepen https://codepen.io/sridhar-katta/pen/NWrxvXo %}

- `Clamp()` for controlling Image width

{% codepen https://codepen.io/sridhar-katta/pen/gOMPxro %}

## Resources:

- [Mozilla Docs](https://developer.mozilla.org/en-US/docs/Web/CSS/clamp)


> If you have any doubts related to this article or anything related to tech or software-engineering in general, drop a comment here or you can message me on twitter [@ksridhar02](https://twitter.com/ksridhar02).
OpenCV- An awesome tool for computer vision in python
Tags: python, machinelearning, opencv, ai
Published: 2020-10-15 07:28:28

To those who don't know what openCV is, it is a library for image/video processing, machine learning and computer vision. This tool also supports C++ and Java but I am little biased towards python and you all know the reason why.

Also, this is my first post on this platform since I am new here and in this post we are going to take a look at what this library is capable to do. Let's get started!

1. **Image Processing** : OpenCV is widely used for image processing and manipulations. The image is represented as a numpy array (3D array if RGB image is being read or 2D array if Grayscale image is being read). Face-recognition is the best example of things that OpenCV can do. ![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/03pycgdxr5f71w5zf2f5.png)
From many useful tools to QR code reader, you can create literally tons of awesome project with it.
Below is the video demonstration of simple QR code reader program that I made using  openCV
{% twitter 1315893570616717312 %}

By using various numpy methods you can experiment around the image properties like the specific color at any pixel/region. Below is a video demonstration of a simple color picker kind of program that opens an image and on left click, shows the hex color code of the area which is clicked and also copies the hex code to the clipboard!
{% twitter 1314804125721194496 %}

2. **Video-Processing** : A video is nothing but tons of frames of image. So basically things which you can do with image can also be done with video files. OpenCV provides you to read video from two streams. You can either pass your web cam as a video source and experiment around your camera properties or pass a valid file path of the compatible video file. One of the best projects which I saw on video-processing was Raghav Khanna's invisible cloak project.
Here is the video demonstration of his project
{%  twitter 1285504929700777985 %}

Apart from these things openCV is widely used in game-automation, self-driving cars, smart CCTV cameras etc.

Now imagine if you have thousands of QR code images in your PC and you are given to draw the histogram graph of sites to which the different QR code belongs to. As a human being you can't scan each and every image to get the information about the QR code.
That's where programming and OpenCV plays key role.
Just crawl through that folder using **os module**, read and scan the image using **OpenCV** and by some algorithms plot a graph using **matplotlib** 

Thanks for reading!
How to Use Scopes in Ruby on Rails
Tags: ruby, rails
Published: 2020-10-15 07:24:53

Scopes are custom queries that you define inside your Rails models with the scope method.

> Every scope takes two arguments:

A name, which you use to call this scope in your code
A lambda, which implements the query


> It looks like this:
```
class User < ApplicationRecord
  scope :active, -> { where("status: 0") }
end
```
As a result of calling a scope, you’ll get an ActiveRecord::Relation object.

Which means you can chain & combine scopes!

> Example:
```
User.active
```

## When To Use Scopes?

> Let’s see an example.
```
def index
  @books = Book.where("LENGTH(title) > 20")
end 
```

This is an index controller action that wants to display books with titles longer than 20 characters.

> It’s fine.

But if you want to use this query in other places, you’re going to have duplicated code.

Duplicated code makes your project harder to maintain.

Let’s move this query into a scope.

> Like this:
```
class Book
  scope :with_long_title, -> { where("LENGTH(title) > 20") }
end
```

> Now our controller action looks like this:
```
def index
  @books = Book.with_long_title
end
```

> Summary
`Good job! As a result of reading this article, you’ve learned how to use Rails scopes in the most effective way.`

`Don’t forget to put this new knowledge into practice so you can remember how it works.`

`Thanks for reading. 🙂`

I’d love to hear thoughts or comments around this. Feel free to email me at ronakabhattrz@gmail.com or hit me up on twitter, @ronakabhattrz.
Typing effect without Javascript
Tags: css, showdev, html, webdev
Published: 2020-10-15 07:21:12

CSS is powerful, you can do a lot of things without JS, also it's important because it controls all design-related aspects of your website. Typography, colors, page layouts, and any other visual aspects of your website are all controlled by mighty CSS.

I rely on CSS, which means I use Javascript as little as possible. Today I will show you the typing effect without any JavaScript!

Let's jump to the code!

```html
<div class="container">
    <div class="type">
      This is one cool effect
    </div>
</div>
```

And a little bit of CSS

```css
.container {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.type {
  width: 35%;
  animation: typing 2s steps(22), blink .5s step-end infinite alternate;
  white-space: nowrap;
  overflow: hidden;
  border-right: 3px solid;
  font-family: monospace;
  font-size: 2em;
}
@keyframes typing {
  from {
    width: 0
  }
}    
@keyframes blink {
  50% {
    border-color: transparent
  }
}
```

This is our result:

![enter image description here](https://i.ibb.co/2dkrTBY/gif-type.gif)

***Thank you all!***
What i have learned?
Tags: hacktoberfest
Published: 2020-10-15 07:17:44

## What I Learned From Hacktoberfest

<!-- What did you learn that can help others contribute to the project you worked on? What did you learn that can help the users of that project?! -->

The best thing which I learned through this event is how to do the pull request and what is its benefit, In this, I have open multiple repositories of a different people and learn different styles of making mine repo to looks better.