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    @stdlib/iter-slice
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    0.0.7 • Public • Published

    iterSlice

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    Create an iterator which returns a subsequence of iterated values from a provided iterator.

    Installation

    npm install @stdlib/iter-slice

    Usage

    var iterSlice = require( '@stdlib/iter-slice' );

    iterSlice( iterator[, begin[, end]] )

    Returns an iterator which returns a subsequence of iterated values from a provided iterator.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    var it = iterSlice( array2iterator( [ 1, 2, 3, 4 ] ) );
    // returns <Object>
    
    var v = it.next().value;
    // returns 1
    
    v = it.next().value;
    // returns 2
    
    v = it.next().value;
    // returns 3
    
    // ...

    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.

    By default, the returned iterator returns a provided iterator's first iterated value through an iterator's last iterated value. To specify an alternative start iteration index (zero-based and inclusive), provide a begin argument.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    var it = iterSlice( array2iterator( [ 1, 2, 3, 4 ] ), 2 );
    // returns <Object>
    
    var v = it.next().value;
    // returns 3
    
    v = it.next().value;
    // returns 4
    
    var bool = it.next().done;
    // returns true

    By default, the returned iterator continues iterating until it consumes all of a provided iterator's iterated values. To specify an end iteration index (zero-based and non-inclusive), provide an end argument.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    var it = iterSlice( array2iterator( [ 1, 2, 3, 4 ] ), 1, 3 );
    // returns <Object>
    
    var v = it.next().value;
    // returns 2
    
    v = it.next().value;
    // returns 3
    
    var bool = it.next().done;
    // returns true

    If begin is greater than or equal to end, the returned iterator does not return any iterated values.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    var it = iterSlice( array2iterator( [ 1, 2, 3, 4 ] ), 3, 1 );
    // returns <Object>
    
    var bool = it.next().done;
    // returns true

    Notes

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

    Examples

    var randu = require( '@stdlib/random-iter-randu' );
    var iterSlice = require( '@stdlib/iter-slice' );
    
    var rand;
    var it;
    var r;
    
    // Create a seeded iterator for generating pseudorandom numbers:
    rand = randu({
        'seed': 1234
    });
    
    // Create an iterator which returns a subsequence of 10 generated numbers:
    it = iterSlice( rand, 10, 20 );
    
    // Perform manual iteration...
    while ( true ) {
        r = it.next();
        if ( r.done ) {
            break;
        }
        console.log( r.value );
    }

    See Also


    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.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/iter-slice

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    72

    Version

    0.0.7

    License

    Apache-2.0

    Unpacked Size

    46.1 kB

    Total Files

    9

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser