@stdlib/math-base-special-roundn

roundn

Round a numeric value to the nearest multiple of 10^n.

Installation

npm install @stdlib/math-base-special-roundn

Usage

var roundn = require( '@stdlib/math-base-special-roundn' );

roundn( x, n )

Rounds a numeric value to the nearest multiple of 10^n.

// Round a value to 2 decimal places:
var v = roundn( 3.141592653589793, -2 );
// returns 3.14

// If n = 0, `roundn` behaves like `round`:
v = roundn( 3.141592653589793, 0 );
// returns 3.0

// Round a value to the nearest thousand:
v = roundn( 12368.0, 3 );
// returns 12000.0

Notes

• When operating on floating-point numbers in bases other than 2, rounding to specified digits can be inexact. For example,

  var x = 0.2 + 0.1;
  // returns 0.30000000000000004
  
  // Should round to 0.3...
  var v = roundn( x, -16 );
  // returns 0.3000000000000001
  

Examples

var randu = require( '@stdlib/random-base-randu' );
var roundn = require( '@stdlib/math-base-special-roundn' );

var x;
var n;
var v;
var i;

for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    n = roundn( randu()*5.0, 0 );
    v = roundn( x, -n );
    console.log( 'x: %d. Number of decimals: %d. Rounded: %d.', x, n, v );
}

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2021. The Stdlib Authors.

Changelog

0.0.4 (2021-07-07)

No changes reported for this release.

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