Computes quantiles for an array ignoring non-numeric values.
npm install compute-nanquantilesnanquantiles
===
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> Computes quantiles for an array ignoring non-numeric values.
`` bash`
$ npm install compute-nanquantiles
For use in the browser, use browserify.
` javascript`
var nanquantiles = require( 'compute-nanquantiles' );
#### nanquantiles( arr, num[, opts] )
Computes _q_-quantiles for an array ignoring non-numeric values. num specifies the number of quantiles to compute. For unsorted primitive arrays,
` javascript
var unsorted = [ 4, 2, null, 5, 3 ];
var q = nanquantiles( unsorted, 2 );
// returns [ 2, 3.5, 5 ]
`
The function accepts the following options:sorted
* : boolean flag indicating if an input array is sorted in __ascending__ order. Default: false.accessor
* : accessor function for accessing values in an object array.
If the input array is already sorted in __ascending__ order, set the sorted option to true.
` javascript
var sorted = [ 2, 3, null, 4, 5 ];
var q = nanquantiles( sorted, 2, {
'sorted': true
});
// returns [ 2, 3.5, 5 ];
`
For object arrays, provide an accessor function for accessing array values
` javascript
var data = [
[1,2],
[2,3],
[3,null],
[4,4],
[5,5]
];
function getValue( d ) {
return d[ 1 ];
}
var q = nanquantiles( data, 2, {
'sorted': true,
'accessor': getValue
});
// returns [ 2, 3.5, 5 ];
`
* For an input array containing no numeric values, the function returns null.
* The function returns the 0th and 100th quantiles; a.k.a., the min and the max. For example, when computing the median,
` javascript
var data = new Array( 11 );
for ( var i = 0; i < data.length; i++ ) {
data[ i ] = i + 1;
}
console.log( nanquantiles( data, 2 ) );
// returns [ 1, 6, 11 ]
`
the function returns [1,6,11], where min = 1, max = 11, and median = 6. Accordingly, you should expect the output to be an array with length = q + 1, where q is the number of quantiles.
` javascript
var nanquantiles = require( 'compute-nanquantiles' );
var data = new Array( 1000 );
for ( var i = 0; i < data.length; i++ ) {
if ( i%2 === 0 ) {
data[ i ] = null;
} else {
data[ i ] = Math.round( Math.random() * 100 );
}
}
console.log( nanquantiles( data, 10 ) );
`
To run the example code from the top-level application directory,
` bash`
$ node ./examples/index.js
Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:
` bash`
$ make test
All new feature development should have corresponding unit tests to validate correct functionality.
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:
` bash`
$ make test-cov
Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,
` bash``
$ make view-cov
---
Copyright © 2015. Philipp Burckhardt.
[npm-image]: http://img.shields.io/npm/v/compute-nanquantiles.svg
[npm-url]: https://npmjs.org/package/compute-nanquantiles
[travis-image]: http://img.shields.io/travis/compute-io/nanquantiles/master.svg
[travis-url]: https://travis-ci.org/compute-io/nanquantiles
[coveralls-image]: https://img.shields.io/coveralls/compute-io/nanquantiles/master.svg
[coveralls-url]: https://coveralls.io/r/compute-io/nanquantiles?branch=master
[dependencies-image]: http://img.shields.io/david/compute-io/nanquantiles.svg
[dependencies-url]: https://david-dm.org/compute-io/nanquantiles
[dev-dependencies-image]: http://img.shields.io/david/dev/compute-io/nanquantiles.svg
[dev-dependencies-url]: https://david-dm.org/dev/compute-io/nanquantiles
[github-issues-image]: http://img.shields.io/github/issues/compute-io/nanquantiles.svg
[github-issues-url]: https://github.com/compute-io/nanquantiles/issues