README
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 );
}
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
License
See LICENSE.
Copyright
Copyright © 2016-2021. The Stdlib Authors.