# isProbabilityArray > Test if a value is an array-like object containing only probabilities.
A **probability** is defined as a numeric value on the interval `[0,1]`.
## Usage ```javascript var isProbabilityArray = require( '@stdlib/assert/is-probability-array' ); ``` #### isProbabilityArray( value ) Tests if a `value` is an array-like object containing **only** probabilities. ```javascript var Number = require( '@stdlib/number/ctor' ); var Uint8Array = require( '@stdlib/array/uint8' ); var bool = isProbabilityArray( [ 0.6, 0.5, 0.25 ] ); // returns true bool = isProbabilityArray( [ 0.6, 0.5, new Number( 0.25 ) ] ); // returns true bool = isProbabilityArray( new Uint8Array( [ 0, 1 ] ) ); // returns true bool = isProbabilityArray( [ 3.14, 0.0 ] ); // returns false ``` #### isProbabilityArray.primitives( value ) Tests if a `value` is an array-like object `array` containing **only** primitive probabilities. ```javascript var Number = require( '@stdlib/number/ctor' ); var bool = isProbabilityArray.primitives( [ 1.0, 0.0, 0.8 ] ); // returns true bool = isProbabilityArray.primitives( [ 0.9, new Number(1.0) ] ); // returns false ``` #### isProbabilityArray.objects( value ) Tests if a `value` is an array-like object `array` containing **only** `Number` objects whose values are probabilities. ```javascript var Number = require( '@stdlib/number/ctor' ); var bool = isProbabilityArray.objects( [ new Number(1.0), new Number(1.0) ] ); // returns true bool = isProbabilityArray.objects( [ 1.0, 0.0, 0.6 ] ); // returns false ```
## Examples ```javascript var Uint8Array = require( '@stdlib/array/uint8' ); var isProbabilityArray = require( '@stdlib/assert/is-probability-array' ); var arr = [ 0.0, 1.0, 0.5 ]; var bool = isProbabilityArray( arr ); // returns true arr = [ 0.5, 0.25, 0.25 ]; bool = isProbabilityArray( arr ); // returns true arr = new Uint8Array( [ 0, 0, 1, 0, 1 ] ); bool = isProbabilityArray( arr ); // returns true arr = [ 3.14, -1.0 ]; bool = isProbabilityArray( arr ); // returns false bool = isProbabilityArray( [] ); // returns false bool = isProbabilityArray( null ); // returns false ```