@stdlib/iter-advance NPM

iterAdvance

Advance an iterator.

Installation

npm install @stdlib/iter-advance

Usage

var iterAdvance = require( '@stdlib/iter-advance' );

iterAdvance( iterator[, n] )

Eagerly advances and returns a provided iterator.

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

var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );
var it = iterAdvance( arr );

var bool = ( it === arr );
// returns true

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

By default, the function eagerly consumes an entire iterator (i.e., n == 1e308). To limit the number of iterations, provide a second argument.

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

var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );
var it = iterAdvance( arr, 4 );

var bool = ( it === arr );
// returns true

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

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

Notes

The function eagerly advances an input iterator n iterations or until the input iterator finishes, whichever comes first.

This function is equivalent to performing manual iteration using a while loop.

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

var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );

var i = 0;
var v;
while ( i < 4 ) {
    v = arr.next();
    if ( v.done ) {
        break;
    }
    i += 1;
}

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

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

Examples

var randu = require( '@stdlib/random-iter-randu' );
var iterLength = require( '@stdlib/iter-length' );
var iterAdvance = require( '@stdlib/iter-advance' );

// Create an iterator which generates uniformly distributed pseudorandom numbers:
var opts = {
    'iter': 100
};
var it1 = randu( opts );

// Discard the first 10 values:
var it2 = iterAdvance( it1, 10 );

// Determine the iterator length:
var len = iterLength( it2 );
// returns 90

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.