2. What is functional programming?

Functional programming produces programs by composing mathematical functions and avoids shared state & mutable data. Lisp (specified in 1958) was among the first languages to support functional programming, and was heavily inspired by lambda calculus. Lisp and many Lisp family languages are still in common use today.

Functional programming is an essential concept in JavaScript (one of the two pillars of JavaScript). Several common functional utilities were added to JavaScript in ES5.

Good to hear:

🔹 Pure functions / function purity.
🔹 Avoid side-effects.
🔹 Simple function composition.
🔹 Examples of functional languages: Lisp, ML, Haskell, Erlang, Clojure, Elm, F Sharp, OCaml, etc…
🔹 Mention of features that support FP: first-class functions, higher order functions, functions as arguments/values.

Red flags:

🔻 No mention of pure functions / avoiding side-effects.
🔻 Unable to provide examples of functional programming languages.
🔻 Unable to identify the features of JavaScript that enable FP.

#javascript #js

3. What is the difference between classical inheritance and prototypal inheritance?
Class Inheritance: instances inherit from classes (like a blueprint — a description of the class), and create sub-class relationships: hierarchical class taxonomies. Instances are typically instantiated via constructor functions with the new keyword. Class inheritance may or may not use the class keyword from ES6.
Prototypal Inheritance: instances inherit directly from other objects. Instances are typically instantiated via factory functions or Object.create(). Instances may be composed from many different objects, allowing for easy selective inheritance.

In JavaScript, prototypal inheritance is simpler &
more flexible than class inheritance.

Good to hear:
🔹 Classes: create tight coupling or hierarchies/taxonomies.
🔹 Prototypes: mentions of concatenative inheritance, prototype delegation, functional inheritance, object composition.

Red Flags:
🔻 No preference for prototypal inheritance & composition over class inheritance.

#javascript #js

4. When is classical inheritance an appropriate choice?

The answer is never, or almost never. Certainly never more than one level. Multi-level class hierarchies are an anti-pattern. I’ve been issuing this challenge for years, and the only answers I’ve ever heard fall into one of several common misconceptions. More frequently, the challenge is met with silence.

“If a feature is sometimes useful
and sometimes dangerous
and if there is a better option
then always use the better option.”
~ Douglas Crockford

Good to hear:

🔹 Rarely, almost never, or never.
🔹 A single level is sometimes OK, from a framework base-class such as React.Component.
🔹 Favor object composition over class inheritance.

#javascript #js

5. When is prototypal inheritance an appropriate choice?

There is more than one type of prototypal inheritance:

- Delegation (i.e., the prototype chain).
- Concatenative (i.e. mixins, Object.assign()).
- Functional (Not to be confused with functional programming. A function used to create a closure for private state/encapsulation).

Each type of prototypal inheritance has its own set of use-cases, but all of them are equally useful in their ability to enable composition, which creates has-a or uses-a or can-do relationships as opposed to the is-a relationship created with class inheritance.

Good to hear:

🔹 In situations where modules or functional programming don’t provide an obvious solution.
🔹 When you need to compose objects from multiple sources.
🔹 Any time you need inheritance.

Red flags:

🔻 No knowledge of when to use prototypes.
🔻 No awareness of mixins or Object.assign().

#javascript #js

Must Do Coding Questions for Companies like Amazon, Microsoft, Adobe, …

Difficulty Level : Medium

https://www.geeksforgeeks.org/must-do-coding-questions-for-companies-like-amazon-microsoft-adobe/

#algorithms #datastructures #dsa

Simple HTML questions for beginners:

1) What is HTML?

HTML stands for Hyper Text Markup Language. It is a language of World Wide Web. It is a standard text formatting language which is used to create and display pages on the Web. It makes the text more interactive and dynamic. It can turn text into images, tables, links.


2) What are Tags?

HTML tags are composed of three things: an opening tag, content and ending tag. Some tags are unclosed tags.

HTML documents contain two things: content and tags

When a web browser reads an HTML document, the browser reads it from top to bottom and left to right. HTML tags are used to create HTML documents and render their properties. Each HTML tags have different properties.

<tag> content </tag>


3) Do all HTML tags have an end tag?

No. There are some HTML tags that don't need a closing tag. For example: <image> tag, <br> tag.


4) What is formatting in HTML?

The HTML formatting is a process of format the text for a better look and feel. It uses different tags to make text bold, italicized, underlined.
More details.


5) How many types of heading does an HTML contain?

The HTML contains six types of headings which are defined with the <h1> to <h6> tags. Each type of heading tag displays different text size from another. So, <h1> is the largest heading tag and <h6> is the smallest one. For example:
<h1>Heading no. 1</h1>
<h2>Heading no. 2</h2>
<h3>Heading no. 3</h3>
<h4>Heading no. 4</h4>
<h5>Heading no. 5</h5>
<h6>Heading no. 6</h6>
More details.

6) How to create a hyperlink in HTML?

The HTML provides an anchor tag to create a hyperlink that links one page to another page. These tags can appear in any of the following ways:

* Unvisited link - It is displayed, underlined and blue.
* Visited link - It is displayed, underlined and purple.
* Active link - It is displayed, underlined and red.


7) Which HTML tag is used to display the data in the tabular form?

The HTML table tag is used to display data in tabular form (row * column). It also manages the layout of the page, e.g., header section, navigation bar, body content, footer section.


8) What are some common lists that are used when designing a page?

There are many common lists which are used to design a page. You can choose any or a combination of the following list types:

* Ordered list - The ordered list displays elements in numbered format. It is represented b

y <o

l> tag.
* Unordered list - The unordered list displays elements in bulleted format. It is represented b

y <u

l> tag.
* Definition list - The definition list displays elements in definition form like in dictionary. Th

e <d

l>

, <dt

> a

nd <d

d> tags are used to define description list.


9) What is the difference between HTML elements and tags?

HTML elements communicate to the browser to render text. When the elements are enclosed by brackets <>, they form HTML tags. Most of the time, tags come in a pair and surround content.


10) What is semantic HTML?

Semantic HTML is a coding style. It is the use of HTML markup to reinforce the semantics or meaning of the content. For example: In semantic H

TML <b> <

/b> tag is not used for bold statement as well as <i> </i> tag is used for italic. Instead of these we

use <strong></stro

ng>

and <em><

/em> tags.

Devops-exercises

ℹ️ This repo contains questions and exercises on various technical topics, sometimes related to DevOps and SRE :)

📊 There are currently 1575 questions

📚 To learn more about DevOps and SRE, check the resources in devops-resources repository

⭐️ 11.8k

https://github.com/bregman-arie/devops-exercises

#devops #jenkins #git #kubernetes #mongo #aws #azure #virtualization #terraform
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57 MySql Interview Questions and Answers

https://www.careerride.com/MySQL-Interview-Questions.aspx

#mysql
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Typical java interview questions sorted by experience


Junior
* Name some of the characteristics of OO programming languages
* What are the access modifiers you know? What does each one do?
* What is the difference between overriding and overloading a method in Java?
* What’s the difference between an Interface and an abstract class?
* Can an Interface extend another Interface?
* What does the static word mean in Java?
* Can a static method be overridden in Java?
* What is Polymorphism? What about Inheritance?
* Can a constructor be inherited?
* Do objects get passed by reference or value in Java? Elaborate on that.
* What’s the difference between using == and .equals on a string?
* What is the hashCode() and equals() used for?
* What does the interface Serializable do? What about Parcelable in Android?
* Why are Array and ArrayList different? When would you use each?
* What’s the difference between an Integer and int?
* What is a ThreadPool? Is it better than using several “simple” threads?
* What the difference between local, instance and class variables?

Mid
* What is reflection?
* What is dependency injection? Can you name a few libraries? (Have you used any?)
* What are strong, soft and weak references in Java?
* What does the keyword synchronized mean?
* Can you have “memory leaks” on Java?
* Do you need to set references to null on Java/Android?
* What does it means to say that a String is immutable?
* What are transient and volatile modifiers?
* What is the finalize() method?
* How does the try{} finally{} works?
* What is the difference between instantiation and initialisation of an object?
* When is a static block run?
* Why are Generics are used in Java?
* Can you mention the design patterns you know? Which of those do you normally use?
* Can you mention some types of testing you know?

Senior
* How does Integer.parseInt() works?
* Do you know what is the “double check locking” problem?
* Do you know the difference between StringBuffer and StringBuilder?
* How is a StringBuilder implemented to avoid the immutable string allocation problem?
* What does Class.forName method do?
* What is Autoboxing and Unboxing?
* What’s the difference between an Enumeration and an Iterator?
* What is the difference between fail-fast and fail safe in Java?
* What is PermGen in Java?
* What is a Java priority queue?
* *s performance influenced by using the same number in different types: Int, Double and Float?
* What is the Java Heap?
* What is daemon thread?
* Can a dead thread be restarted?

Source: medium.

Single Number

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example 1:

Input: nums = [2,2,1]
Output: 1

Example 2:

Input: nums = [4,1,2,1,2]
Output: 4

Example 3:

Input: nums = [1]
Output: 1

Asked by:
Google, Amazon, Facebook

🔗 Link to leetcode question:

Python-programming-exercises

Creator: Jeffrey Hu
Stars ⭐️: 12.5k
Forked By : 5.3k
GitHub Repo: https://github.com/zhiwehu/Python-programming-exercises

Jeffrey Hu’s GitHub repo is a fairly straightforward one. His repo has more than 100 Python programming challenges that cater to new developers, intermediate developers, as well as veteran professionals.

https://github.com/zhiwehu/Python-programming-exercises

#python
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Top 100 Python Interview Questions You Must Prepare In 2021

https://www.edureka.co/blog/interview-questions/python-interview-questions/

#python
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I got few requests for Python Interview Questions in @bigdataspecialist channel
Here are some recommendations:

* 26 Essential Python Interview Questions from Adeva
* 20 Python interview questions and answers
* 11 Essential Python Interview Questions from Toptal
* A listing of questions that could potentially be asked for a python job listing
* Interview Questions for both beginners and experts

#python
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ReactJS Interview questions

https://www.educba.com/reactjs-interview-questions/

#javascript #js #reactjs
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15 Essential C# Interview Questions
by Toptal

https://www.toptal.com/c-sharp/interview-questions

PS. sorry for not posting for a long time, we are working on programming quizzes which will help you prepare for programming interviews and generally improve your programming knowledge.

Stay tuned