README.md

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!

iterDedupe

Create an iterator which removes consecutive duplicated values.

Usage

import iterDedupe from 'https://cdn.jsdelivr.net/gh/stdlib-js/iter-dedupe@deno/mod.js';

iterDedupe( iterator[, limit] )

Returns an iterator which removes consecutive duplicated values.

import array2iterator from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-to-iterator@deno/mod.js';

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

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

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

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

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

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.

The returned iterator removes consecutive duplicated values and does not return globally unique values.

import array2iterator from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-to-iterator@deno/mod.js';

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

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

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

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

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

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

To specify the number of allowed consecutive duplicated values, provide a second argument.

import array2iterator from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-to-iterator@deno/mod.js';

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

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

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

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

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

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

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

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

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

Notes

• NaN values are considered distinct.

  import array2iterator from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-to-iterator@deno/mod.js';
  
  var it = iterDedupe( array2iterator( [ NaN, NaN, NaN, NaN ] ) );
  // returns <Object>
  
  var v = it.next().value;
  // returns NaN
  
  v = it.next().value;
  // returns NaN
  
  v = it.next().value;
  // returns NaN
  
  v = it.next().value;
  // returns NaN
  
  var bool = it.next().done;
  // returns true

• Uniqueness is determined according to strict equality. Accordingly, objects are not checked for deep equality.

  import array2iterator from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-to-iterator@deno/mod.js';
  
  var it = iterDedupe( array2iterator( [ {}, {}, {}, {} ] ) );
  // returns <Object>
  
  var v = it.next().value;
  // returns {}
  
  v = it.next().value;
  // returns {}
  
  v = it.next().value;
  // returns {}
  
  v = it.next().value;
  // returns {}
  
  var bool = it.next().done;
  // returns true

• If an environment supports Symbol.iterator and a provided iterator is iterable, the returned iterator is iterable.

Examples

import randi from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-iter-discrete-uniform@deno/mod.js';
import iterDedupe from 'https://cdn.jsdelivr.net/gh/stdlib-js/iter-dedupe@deno/mod.js';

// Create a seeded iterator for generating pseudorandom integers on the interval [1,3]:
var rand = randi( 1, 3, {
    'seed': 1234,
    'iter': 100
});

// Create an iterator which limits "runs" to at most 3 values:
var it = iterDedupe( rand, 3 );

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

---

See Also

• @stdlib/iter-dedupe-by: create an iterator which removes consecutive values that resolve to the same value according to a provided function.
• @stdlib/iter-unique: create an iterator which returns unique values.

---

Notice

This package is part of stdlib, a standard library 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.