How to round whole numbers to whole numbers using JavaScript?

Question

How to round whole numbers to whole numbers using JavaScript?

Looking to manipulate some numbers in JavaScript. Let's say we have x = 320232, y = 2301, and z = 12020305. The goal is to round these numbers to the nearest tens, hundreds, or thousands place. Thus, we want them to become x = 320000, y = 2300, and z = 12000000.

I attempted using Math.round and Math.floor, but those methods are designed for decimal values rather than whole numbers like what we have here.

My question: Is there a way to round off whole numbers in JavaScript? If so, how can we accomplish this task?

Edit note: Specifically aiming to round to the nearest starting 3-digit place as shown in the given variables. For example, if another variable existed such as c = 423841, it should be rounded off to c = 424000.

javascript math

Answer 1

Answer №1

If you want to adjust the digits using logarithm of ten, this code snippet may be helpful:

const
    modifyDigits = n => value => {
        if (!value) return 0;
        const length = Math.floor(Math.log10(Math.abs(value))) - n + 1;

        return Math.round(value / 10 ** length) * 10 ** length;
    };

console.log([0, -9876, 320232, 2301, 12020305, 123456789].map(modifyDigits(3)));

Answer 2

If you want to adjust the digits using logarithm of ten, this code snippet may be helpful:

const
    modifyDigits = n => value => {
        if (!value) return 0;
        const length = Math.floor(Math.log10(Math.abs(value))) - n + 1;

        return Math.round(value / 10 ** length) * 10 ** length;
    };

console.log([0, -9876, 320232, 2301, 12020305, 123456789].map(modifyDigits(3)));

Answer 3

Answer №2

To find the solution, start by determining the number of figures that need to be rounded off before applying the rounding process.

For example, using Math.round(1234/100)*100 would result in 1200, which can be used as a reference for rounding. The next step is figuring out what value should replace 100 in this scenario.

This involves adding a 1 followed by LENGTH - 3 zeros. To calculate this number, use the formula 10 raised to the power of LENGTH - 3. In JavaScript, it's represented as 10 ** (length - 3).

var x = 320232;
var y = 2301;
var z = 12020305;

function my_round(number){
  var org_number = number;
  
  // calculating integer number
  var count = 0;
  if (number >= 1) ++count;

  while (number / 10 >= 1) {
    number /= 10;
    ++count;
  }
  
  // length - 3
  count = Math.round(count) - 3;
  if (count < 0){
    count = 0;
  }
  
  // 10 to the power of (length - 3)
  var helper = 10 ** count;
  
  return Math.round(org_number/helper)*helper;
}

alert(my_round(x));
alert(my_round(y));
alert(my_round(z));

While the code may not be the most aesthetically pleasing, efforts were made to ensure it remains understandable and explanatory.

Answer 4

To find the solution, start by determining the number of figures that need to be rounded off before applying the rounding process.

For example, using Math.round(1234/100)*100 would result in 1200, which can be used as a reference for rounding. The next step is figuring out what value should replace 100 in this scenario.

This involves adding a 1 followed by LENGTH - 3 zeros. To calculate this number, use the formula 10 raised to the power of LENGTH - 3. In JavaScript, it's represented as 10 ** (length - 3).

var x = 320232;
var y = 2301;
var z = 12020305;

function my_round(number){
  var org_number = number;
  
  // calculating integer number
  var count = 0;
  if (number >= 1) ++count;

  while (number / 10 >= 1) {
    number /= 10;
    ++count;
  }
  
  // length - 3
  count = Math.round(count) - 3;
  if (count < 0){
    count = 0;
  }
  
  // 10 to the power of (length - 3)
  var helper = 10 ** count;
  
  return Math.round(org_number/helper)*helper;
}

alert(my_round(x));
alert(my_round(y));
alert(my_round(z));

While the code may not be the most aesthetically pleasing, efforts were made to ensure it remains understandable and explanatory.

Answer 5

Answer №3

Here is a solution that should do the trick:

function roundToNthDecimal(input, n) {
    let powerOfTen = 10 ** n;
    return Math.round(input / powerOfTen) * powerOfTen;
}

console.log([320232, 2301, 12020305, 423841].map(input => roundToNthDecimal(input, 3)));

Output: [320000, 2000, 12020000, 424000]

Answer 6

Here is a solution that should do the trick:

function roundToNthDecimal(input, n) {
    let powerOfTen = 10 ** n;
    return Math.round(input / powerOfTen) * powerOfTen;
}

console.log([320232, 2301, 12020305, 423841].map(input => roundToNthDecimal(input, 3)));

Output: [320000, 2000, 12020000, 424000]

How to round whole numbers to whole numbers using JavaScript?

Answer №1

Answer №2

Answer №3

Similar questions

MongoDB error codes and their associated HTTP status codes are important for developers to understand

Creating a cutting-edge mobile application using PhoneGap and Node.js

"Integrate a URL segment into the primary URL with the help of AngularJS or JavaScript

Is there a way to transform a .pcm file to a wav file using node.js?

Troubleshooting problem in Vercel with Next.js 13 application - encountering "Module not found" error

Sometimes jQuery may require multiple executions with just one click

Add axios requests to the axios.all array

Should I fork and customize npm package: Source or Distribution? How to handle the distribution files?

Multi selection dropdown feature in Angular failing to populate the options

The use of jQuery addClass does not produce any changes

Trouble arises with the chrome extension code for retrieving tweets from Twitter

Steps to validate individual input text fields that create a date and display an error message if the date is not valid

Placing a moveable object in a designated spot for dropping at the desired location

Using a wildcard (*) to select elements with JQuery

The Ajax data was not displayed in the console log, instead an error message was returned stating "http://localhost/IFICSV3/public/sla/sla/getbranch/180 not found"

How can MessagePorts be effectively utilized in electron Js?

Discover how to retrieve the calculated percentage within CSS with the assistance of jQuery specifically designed for Webkit

Why does attempting to access an undefined property not trigger an error?

Tips for creating a scrolling animation effect with images

What is the best way to deliver an HTTP request from the controller to my Ajax function?