Dean Gislason

Dean Gislason

1597288800

Demystifying Regular Expressions with JavaScript

Regular expressions can be scary, but they are a powerful feature any programmer should know. Let’s learn about them together.

The first time I encounter a regular expression was many years ago, but I still remember my first thoughts on it:

  1. What is this string-like thing?
  2. I rather don’t touch it, looks scary

I don’t remember quite well what that regex was doing, or how exactly looked like, but it scared me to death. Looking in retrospective I realize that it was probably not scary at all and that in fact, it was an easy way to solve the problem in hand. But why did I got this feeling? It’s just the awkwardness of the syntax, they certainly look strange, and if you don’t know what they are, they look very complicated.

My intention here is not to scare you out, regex can be simple once we understand them, but if you don’t and you look at something like this:

^\(*\d{3}\)*( |-)*\d{3}( |-)*\d{4}$

Can be intimidating…

Today we are going to demystify regular expressions, we will see what they are, what they are useful for, and how you can design your regular expressions to solve problems.

#javascript #developer #programming #web-development

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Demystifying Regular Expressions with JavaScript

Mad Libs: Using regular expressions

From Tiny Python Projects by Ken Youens-Clark

Everyone loves Mad Libs! And everyone loves Python. This article shows you how to have fun with both and learn some programming skills along the way.


Take 40% off Tiny Python Projects by entering fccclark into the discount code box at checkout at manning.com.


When I was a wee lad, we used to play at Mad Libs for hours and hours. This was before computers, mind you, before televisions or radio or even paper! No, scratch that, we had paper. Anyway, the point is we only had Mad Libs to play, and we loved it! And now you must play!

We’ll write a program called mad.py  which reads a file given as a positional argument and finds all the placeholders noted in angle brackets like <verb>  or <adjective> . For each placeholder, we’ll prompt the user for the part of speech being requested like “Give me a verb” and “Give me an adjective.” (Notice that you’ll need to use the correct article.) Each value from the user replaces the placeholder in the text, and if the user says “drive” for “verb,” then <verb>  in the text replaces with drive . When all the placeholders have been replaced with inputs from the user, print out the new text.

#python #regular-expressions #python-programming #python3 #mad libs: using regular expressions #using regular expressions

Madyson  Reilly

Madyson Reilly

1601055000

Regular Expressions: What and Why?

Regular expressions is a powerful search and replace technique that you probably have used even without knowing. Be it your text editor’s “Find and Replace” feature, validation of your http request body using a third party npm module or your terminal’s ability to return list of files based on some pattern, all of them use Regular Expressions in one way or the other. It is not a concept that programmers must definitely learn but by knowing it you are able to reduce the complexity of your code in some cases.

_In this tutorial we will be learning the key concepts as well as some use cases of Regular Expressions in _javascript.

How do you write a Regular Expression?

There are two ways of writing Regular expressions in Javascript. One is by creating a **literal **and the other is using **RegExp **constructor.

//Literal
const myRegex=/cat/ig

//RegExp
const myRegex=new RegExp('cat','ig')

While both types of expressions will return the same output when tested on a particular string, the benefit of using the RegExp constructor is that it is evaluated at runtime hence allowing use of javascript variables for dynamic regular expressions. Moreover as seen in this benchmark test the RegExp constructor performs better than the literal regular expression in pattern matching.

The syntax in either type of expression consists of two parts:

  • pattern : The pattern that has to be matched in a string.
  • flags : these are modifiers which are rules that describe how pattern matching will be performed.

#regular-expressions #javascript #programming #js #regex #express

Rahul Jangid

1622207074

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

  • For single line comment in JavaScript we have to use // (double slashes)
  • For multiple line comments we have to use / * – – * /
<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Madyson  Reilly

Madyson Reilly

1601069940

Function Expression vs Function Declaration in JavaScript

Function Expression vs Function Declaration in JavaScript.

It was until during one of the JavaScript mock interviews did I came across the term function expression.

The question was: What is the difference between these two syntax?

function x(){

}

let x = function(){

}

I was clueless for a moment. After thinking a little, I could only come up with: the second syntax invokes an _anonymous _function and is assigned to a variable.

I was alien to the term hoisting.

In this article, we will acquaint ourselves with three simple terms: function declaration,_ function expression, _and hoisting.

What is function declaration?

Function declaration is also known as _function statement. _It contains the name of the function, parameters, and a return statement. **Naming the function **is what sets function declaration apart. Parameters and return statement is optional.

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Function Declaration

What is function expression?

Function expression also has a name, parameters, and return statement. All of which are optional. The important thing to bear in mind is: the function here is _assigned _to a JavaScript variable.

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Function Expression

#function-expression #function-declaration #functions-in-javascript #coding #javascript #express

Hire Dedicated JavaScript Developers -Hire JavaScript Developers

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Does your business need an interactive website or app?

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The technology used to develop the overall app by the developers from WebClues Infotech is at par with the latest available technology.

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#hire dedicated javascript developers #hire javascript developers #top javascript developers for hire #hire javascript developer #hire a freelancer for javascript developer #hire the best javascript developers