@stdlib/array-from-iterator
v0.2.2
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Create (or fill) an array from an iterator.
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iterator2array
Create (or fill) an array from an iterator.
Installation
npm install @stdlib/array-from-iterator
Usage
var iterator2array = require( '@stdlib/array-from-iterator' );
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 valueindex
: 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
var Float64Array = require( '@stdlib/array-float64' );
var randu = require( '@stdlib/random-iter-randu' );
var iterator2array = require( '@stdlib/array-from-iterator' );
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 ] );
}
See Also
@stdlib/array-to-iterator
: create an iterator from an array-like object.@stdlib/iter-to-array-view
: fill an array-like object view with values returned from an 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.