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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!

iterator2array

NPM version Build Status Coverage Status

Create (or fill) an array from an iterator.

Usage

To use in Observable,

iterator2array = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/array-from-iterator@umd/browser.js' )

To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:

var iterator2array = require( 'path/to/vendor/umd/array-from-iterator/index.js' )

To include the bundle in a webpage,

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-from-iterator@umd/browser.js"></script>

If no recognized module system is present, access bundle contents via the global scope:

<script type="text/javascript">
(function () {
    window.iterator2array;
})();
</script>

iterator2array( iterator[, out][, mapFcn[, thisArg]] )

Creates (or fills) an array from an iterator.

var randu = require( '@stdlib/random-iter-randu' );

var opts = {
    'iter': 10
};

var arr = iterator2array( randu( opts ) );
// returns <Array>

By default, the function creates and fills a generic array. To fill an array-like object, provide an out argument.

var Float64Array = require( '@stdlib/array-float64' );
var randu = require( '@stdlib/random-iter-randu' );

var out = new Float64Array( 10 );

var arr = iterator2array( randu(), out );
// returns <Float64Array>

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

To invoke a function for each iterated value, provide a callback function.

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

function fcn( v ) {
    return v * 10.0;
}

var arr = iterator2array( array2iterator( [ 1, 2, 3, 4 ] ), fcn );
// returns [ 10.0, 20.0, 30.0, 40.0 ]

The invoked function is provided two arguments:

  • value: iterated value.
  • index: iterated value index.
var Float64Array = require( '@stdlib/array-float64' );
var randu = require( '@stdlib/random-iter-randu' );

function fcn( v, i ) {
    return v * (i+1);
}

var arr = iterator2array( randu(), new Float64Array( 10 ), fcn );
// returns <Float64Array>

To set the callback function execution context, provide a thisArg.

var Float64Array = require( '@stdlib/array-float64' );
var randu = require( '@stdlib/random-iter-randu' );

function fcn( v ) {
    this.count += 1;
    return v * 10.0;
}

var ctx = {
    'count': 0
};

var arr = iterator2array( randu(), new Float64Array( 10 ), fcn, ctx );
// returns <Float64Array>

var count = ctx.count;
// returns 10

Notes

  • If provided an output array, the function fills the output array with iterated values.
  • Iteration stops when an output array is full or an iterator finishes; whichever comes first.
  • By providing an output typed array, one avoids the temporary memory allocation when using the built-in TypedArray.from.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-iter-randu@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-from-iterator@umd/browser.js"></script>
<script type="text/javascript">
(function () {

var opts;
var arr;
var it;
var i;

function scale( v, i ) {
    return v * (i+1);
}

// Create an iterator for generating uniformly distributed pseudorandom numbers:
opts = {
    'iter': 10
};
it = randu( opts );

// Fill an array with scaled iterator values:
arr = iterator2array( it, new Float64Array( opts.iter ), scale );

for ( i = 0; i < arr.length; i++ ) {
    console.log( arr[ i ] );
}

})();
</script>
</body>
</html>

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.

Community

Chat

License

See LICENSE.

Copyright

Copyright © 2016-2025. The Stdlib Authors.