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iterHead
Create an iterator which returns the first
n
values of a provided iterator.
Installation
npm install @stdlib/iter-head
Usage
var iterHead = require( '@stdlib/iter-head' );
iterHead( iterator, n )
Returns an iterator which returns the first n
values of a provided iterator
.
var array2iterator = require( '@stdlib/array-to-iterator' );
var it = iterHead( array2iterator( [ 1, 2, 3, 4 ] ), 2 );
// returns <Object>
var v = it.next().value;
// returns 1
v = it.next().value;
// returns 2
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.
Notes
Examples
var randu = require( '@stdlib/random-iter-randu' );
var iterHead = require( '@stdlib/iter-head' );
// Create a seeded iterator for generating pseudorandom numbers:
var rand = randu({
'seed': 1234
});
// Create an iterator which returns the first 10 generated numbers:
var it = iterHead( rand, 10 );
// Perform manual iteration...
var r;
while ( true ) {
r = it.next();
if ( r.done ) {
break;
}
console.log( r.value );
}
See Also
-
@stdlib/iter-first
: return the first iterated value. -
@stdlib/iter-slice
: create an iterator which returns a subsequence of iterated values from a provided iterator.
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
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.