@stdlib/iter-unique

About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

iterUnique

Create an iterator which returns unique values.

Installation

npm install @stdlib/iter-unique

Usage

var iterUnique = require( '@stdlib/iter-unique' );

iterUnique( iterator )

Returns an iterator which returns unique values.

var array2iterator = require( '@stdlib/array-to-iterator' );

var it = iterUnique( array2iterator( [ 2, 1, 1, 2, 4, 3, 4, 3 ] ) );
// returns <Object>

var v = it.next().value;
// returns 2

v = it.next().value;
// returns 1

v = it.next().value;
// returns 4

v = it.next().value;
// returns 3

var bool = it.next().done;
// returns true

The returned iterator protocol-compliant object has the following properties:

• next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.
• return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

Notes

• Value "uniqueness" is determined according to strict equality.
• A returned iterator internally buffers unique values and, thus, has O(N) memory requirements.
• If an environment supports Symbol.iterator and a provided iterator is iterable, the returned iterator is iterable.

Examples

var discreteUniform = require( '@stdlib/random-iter-discrete-uniform' );
var iterUnique = require( '@stdlib/iter-unique' );

// Create a seeded iterator which can generate 1000 pseudorandom numbers:
var rand = discreteUniform( 1, 10, {
    'seed': 1234,
    'iter': 1000
});

// Create an iterator which returns unique values:
var it = iterUnique( rand );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

---

See Also

• @stdlib/iter-unique-by: create an iterator which returns unique values according to a predicate function.
• @stdlib/iter-unique-by-hash: create an iterator which returns unique values according to a hash function.

---

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, 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

---

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.