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!
Create an iterator which removes consecutive values that resolve to the same value according to a provided function.
npm install @stdlib/iter-dedupe-by
var iterDedupeBy = require( '@stdlib/iter-dedupe-by' );
Returns an iterator which removes consecutive values that resolve to the same value according to a provided function.
var array2iterator = require( '@stdlib/array-to-iterator' );
function fcn( v ) {
return v;
}
var arr = array2iterator( [ 1, 1, 2, 3, 3, 3, 4, 4 ] );
var it = iterDedupeBy( arr, fcn );
// 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 adone
property having aboolean
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 callback function is provided five arguments:
- curr: current source iterated value.
- sprev: previous source iterated value.
- dprev: previous downstream iterated value.
- index: source iteration index (zero-based).
- acc: previous resolved value.
The returned iterator removes consecutive values which resolve to the same value and does not return globally "unique" values.
var array2iterator = require( '@stdlib/array-to-iterator' );
function fcn( v ) {
return v;
}
var arr = array2iterator( [ 1, 1, 2, 1, 1, 2 ] );
var it = iterDedupeBy( arr, fcn );
// 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 limit
argument.
var array2iterator = require( '@stdlib/array-to-iterator' );
function fcn( v ) {
return v;
}
var arr = array2iterator( [ 1, 1, 2, 3, 3, 3, 3, 4, 4, 4 ] );
var it = iterDedupeBy( arr, 2, fcn );
// 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
var randi = require( '@stdlib/random-iter-discrete-uniform' );
var iterDedupe = require( '@stdlib/iter-dedupe' );
var iterDedupeBy = require( '@stdlib/iter-dedupe-by' );
function fcn( curr, sprev, dprev, i, acc ) {
if ( curr < dprev ) {
return 1;
}
if ( curr === dprev ) {
return acc; // ensures that duplicate values are removed
}
// curr > dprev
return -1;
}
// Create a seeded iterator for generating pseudorandom integers:
var rand = randi( 1, 10, {
'seed': 1234,
'iter': 100
});
// Create an iterator which removes consecutive duplicated values:
var deduped = iterDedupe( rand );
// Create an iterator which forces consecutive values to follow an alternating less than, greater than pattern:
var it = iterDedupeBy( deduped, fcn );
// Perform manual iteration...
var v;
while ( true ) {
v = it.next();
if ( v.done ) {
break;
}
console.log( v.value );
}
-
@stdlib/iter-dedupe
: create an iterator which removes consecutive duplicated values. -
@stdlib/iter-unique
: create an iterator which returns unique values.
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.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.