Poppy Cooke

Poppy Cooke

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Working with Numbers in JavaScript

Numbers and mathematics come into most scripts at some point, be it in the form of the simple arithmetic required to add up prices and work out sales tax, the process of generating and using random numbers, or the more complex mathematics involved animation.

In this article we’ll meet the basic constructs for number crunching in JavaScript, and look at some fairly simple, but useful snippets.

Doing Math in JavaScript

JavaScript provides syntax for basic arithmetic, as well as a range of properties and methods for performing more complex tasks.

There are five arithmetic operators in JavaScript, each of which is represented by a special character: multiplication (*), division (/), addition (+), subtraction (-), and modulus(%).

Math Operators

In addition to these basic operators, JavaScript has a built-in Math object that provides a range of mathematical methods and properties. The most useful methods are:

Math.ceil : rounds a number upwards, so Math.ceil(8.23) returns 9

Math.floor : rounds a number downwards, so* Math.floor(23.8)* returns 23

Math.round : rounds the number to the nearest integer, so *Math.round(8.3) *returns 8, while Math.round(2.8) returns 3

Math.pow : raises one number to the power of another so *Math.pow(2,3)*returns

Math.sqrt : returns the square root of a number do *Math.sqrt(9) *returns 3

Math.random : returns a pseudorandom number between zero and one

Rounding a Number to x Decimal Places

In some applications, you may need to round the result to a certain number of decimal places. For instance, you may want to display temprature values in 0.1 degree increments, even you though your script has access to more precise values.

So the question is how to do it?

We can write a function that will round to any number of places, as follows:

JavaScript function to round any numbers

So, for example, if we started with a number like n = 3.492867, we could call roundTo(n, 0) to get 3 or roundTo(n, 2) to get 3.49

Creating and Constraining Random Numbers

Random numbers can be used as the basis for any task that needs to have a random or semi-random aspect.

We already know how to generate a random number between 0 and 1 by using Math.random() function but what if we need random numbers between 0-100 or maybe 8-23 or 23-1995 etc.

Well there is a solution

We can obtain a random integer within specified limits using a combination of the Math object’s random and round methods, which we saw in “Doing Math in JavaScript”.

function to generate random number between any two numbers.

so, for example we could generate a number between 0 and 100 by calling randomBetween(0, 100), or a number between 8 and 1995 by calling radomBetween(8, 1995).

using randomBetween() function to get random numbers.

Converting a Number to a String

Once you’ve finished a calculation, you might want to turn the output into something more readable, such as formatting a value to represent currency.To do this we must convert the number to a string.

The most direct means of converting a number to a string is to built -in String constructor function:

converting number to string using built-in String constructor

You can also use toString method, which is provided for every number value in JavaScript:

converting string using toString() method

Another useful technique is string concatenation (joining strings together), which returns a string even if some of the input values are numbers:

string concatenation

Converting a String to a Number

Like Number to String, conversion of String to a Number is also possible.

In general, you can treat a JavaScript string that contains a number as if it were a number, and JavaScript will Perform the string-to-number conversion for you automatically. But sometimes you need to extract a number from a string, or exercise more control over how the conversion is done.

The most direct means of converting a string to a number is to use the built-in Number constructor function:

conversion using built-in Number constructor function

Another handy technique is to use tha parseInt and ParseFloat functions, which will attempt to find and return an integer or decimal number at the start of a string.

conversion using parseInt and parseFloat

**note : **If the first character of the input is not a digit or some other numerical character , these functions will not be ale to return a number. In such cases. they’ll return the special value NaN (Not a Number).

#javascript

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Working with Numbers in JavaScript

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

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Hire Dedicated JavaScript Developers -Hire JavaScript Developers

It is said that a digital resource a business has must be interactive in nature, so the website or the business app should be interactive. How do you make the app interactive? With the use of JavaScript.

Does your business need an interactive website or app?

Hire Dedicated JavaScript Developer from WebClues Infotech as the developer we offer is highly skilled and expert in what they do. Our developers are collaborative in nature and work with complete transparency with the customers.

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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Niraj Kafle

1589255577

The essential JavaScript concepts that you should understand

As a JavaScript developer of any level, you need to understand its foundational concepts and some of the new ideas that help us developing code. In this article, we are going to review 16 basic concepts. So without further ado, let’s get to it.

#javascript-interview #javascript-development #javascript-fundamental #javascript #javascript-tips

Ajay Kapoor

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Santosh J

1622036598

JavaScript compound assignment operators

JavaScript is unarguablly one of the most common things you’ll learn when you start programming for the web. Here’s a small post on JavaScript compound assignment operators and how we use them.

The compound assignment operators consist of a binary operator and the simple assignment operator.

The binary operators, work with two operands. For example a+b where + is the operator and the a, b are operands. Simple assignment operator is used to assign values to a variable(s).

It’s quite common to modify values stored in variables. To make this process a little quicker, we use compound assignment operators.

They are:

  • +=
  • -+
  • *=
  • /=

You can also check my video tutorial compound assignment operators.

Let’s consider an example. Suppose price = 5 and we want to add ten more to it.

var price = 5;
price = price + 10;

We added ten to price. Look at the repetitive price variable. We could easily use a compound += to reduce this. We do this instead.

price += 5;

Awesome. Isn’t it? What’s the value of price now? Practice and comment below. If you don’t know how to practice check these lessons.

Lets bring down the price by 5 again and display it.
We use console.log command to display what is stored in the variable. It is very help for debugging.
Debugging let’s you find errors or bugs in your code. More on this later.

price -= 5;
console.log(price);

Lets multiply price and show it.

price *=5;
console.log(price);

and finally we will divide it.

price /=5;
console.log(price);

If you have any doubts, comment below.

#javascript #javascript compound assignment operators #javascript binary operators #javascript simple assignment operator #doers javascript