# compute-nanmean

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

## Stats

StarsIssuesVersionUpdatedCreatedSize
compute-nanmean
401.0.210 years ago10 years ago

nanmean
!NPM versionnpm-imagenpm-url !Build Statustravis-imagetravis-url !Coverage Statuscoveralls-imagecoveralls-url !Dependenciesdependencies-imagedependencies-url
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``