nanmean

Computes the arithmetic mean over an array of values ignoring any values which are not numeric.

Installation

$ npm install compute-nanmean

For use in the browser, use browserify.

Usage

To use the module,

var nanmean = require( 'compute-nanmean' );

nanmean( arr )

Computes the arithmetic mean while ignoring any non-numeric values.

var data = [ 1, NaN, 2, 3, NaN ];

var mu = nanmean( data );
// returns 2

Examples

var nanmean = require( 'compute-nanmean' );

var data = new Array( 1000 );

for ( var i = 0; i < data.length; i++ ) {
	if ( i%5 === 0 ) {
		data[ i ] = NaN;
	} else {
		data[ i ] = Math.random() * 100;
	}
}

console.log( nanmean( data ) );

To run the example code from the top-level application directory,

$ node ./examples/index.js

Notes

The mean value of an array containing non-numeric values is equal to the mean value of an equivalent array which contains only the numeric values. Hence,

var d1 = [ 1, NaN, 2, 3, NaN ],
	d2 = [ 1, 2, 3 ];

console.log( nanmean( d1 ) === nanmean( d2 ) );
// returns true

Tests

Unit

Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

License

MIT license.

Copyright

Copyright © 2014. Athan Reines.