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isBetween

Test if a value is between two values.

Usage

import isBetween from 'https://cdn.jsdelivr.net/gh/stdlib-js/assert-is-between@deno/mod.js';

isBetween( value, a, b[, left, right] )

Tests if a value is between two values a (left comparison value) and b (right comparison value).

var bool = isBetween( 4, 3, 5 );
// returns true

bool = isBetween( 2, 3, 5 );
// returns false

bool = isBetween( 6, 3, 5 );
// returns false

By default, the function assumes that a and b are inclusive.

var bool = isBetween( 3, 3, 5 );
// returns true

bool = isBetween( 3, 3, 5, 'closed', 'closed' );
// returns true

bool = isBetween( 5, 3, 5 );
// returns true

bool = isBetween( 5, 3, 5, 'closed', 'closed' );
// returns true

To make a and/or b exclusive, set the respective arguments to 'open'.

var bool = isBetween( 3, 3, 5, 'open', 'closed' );
// returns false

bool = isBetween( 5, 3, 5, 'closed', 'open' );
// returns false

Notes

• If a and b are inclusive, the comparison is equivalent to

  a <= v <= b
  

• If a is exclusive and b is inclusive, the comparison is equivalent to

  a < v <= b
  

• If a is inclusive and b is exclusive, the comparison is equivalent to

  a <= v < b
  

• If a and b are exclusive, the comparison is equivalent to

  a < v < b
  

• If provided non-numeric values, comparisons are performed according to lexicographic order.

Examples

import randu from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@deno/mod.js';
import round from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-round@deno/mod.js';
import isBetween from 'https://cdn.jsdelivr.net/gh/stdlib-js/assert-is-between@deno/mod.js';

var bool;
var a;
var b;
var v;
var i;

for ( i = 0; i < 100; i++ ) {
    a = round( (randu()*10.0) + 5.0 );
    b = round( (randu()*10.0) + 15.0 );
    v = round( randu()*25.0 );
    bool = isBetween( v, a, b, 'open', 'closed' );
    console.log( '%d < %d <= %d: %s', a, v, b, bool.toString() );
}

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See Also

• @stdlib/assert-is-between-array: test if a value is an array-like object where every element is between two values.

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Notice

This package is part of stdlib, a standard library 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 © 2016-2025. The Stdlib Authors.