@stdlib/math-iter-tools-map2
v0.2.2
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Create an iterator which invokes a binary function accepting numeric arguments for each iterated value.
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iterMap2
Create an iterator which invokes a binary function accepting numeric arguments for each iterated value.
Installation
npm install @stdlib/math-iter-tools-map2
Usage
var iterMap2 = require( '@stdlib/math-iter-tools-map2' );
iterMap2( iter0, iter1, fcn[, options] )
Returns an iterator which invokes a binary function
accepting numeric arguments for each iterated value.
var array2iterator = require( '@stdlib/array-to-iterator' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var it1 = array2iterator( [ 1.0, 2.0, 3.0, 4.0 ] );
var it2 = array2iterator( [ 1.0, -1.0, -1.0, 1.0 ] );
var it = iterMap2( it1, it2, copysign );
// returns <Object>
var r = it.next().value;
// returns 1.0
r = it.next().value;
// returns -2.0
r = it.next().value;
// returns -3.0
// ...
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.
The invoked function
is provided two arguments:
var array2iterator = require( '@stdlib/array-to-iterator' );
function fcn( x, y ) {
return x + y + 10;
}
var it1 = array2iterator( [ 1, 2, 3, 4 ] );
var it2 = array2iterator( [ 1, 2, 3, 4 ] );
var it = iterMap2( it1, it2, fcn );
// returns <Object>
var r = it.next().value;
// returns 12
r = it.next().value;
// returns 14
r = it.next().value;
// returns 16
// ...
The function supports the following options
:
- invalid: return value when an input iterator yields a non-numeric value. Default:
NaN
.
By default, the function returns an iterator which returns NaN
when an input iterator yields a non-numeric value. To specify a different return value, set the invalid
option.
var array2iterator = require( '@stdlib/array-to-iterator' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var it1 = array2iterator( [ '1.0', '2.0', '3.0' ] );
var it2 = array2iterator( [ 1.0, 2.0, 3.0 ] );
var opts = {
'invalid': null
};
var it = iterMap2( it1, it2, copysign, opts );
// returns <Object>
var v = it.next().value;
// returns null
v = it.next().value;
// returns null
// ...
If provided a numeric value as an iterator
argument, the value is broadcast as an infinite iterator which always returns the provided value.
var array2iterator = require( '@stdlib/array-to-iterator' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var it1 = array2iterator( [ 1.0, 2.0 ] );
var it = iterMap2( it1, -4.0, copysign );
// returns <Object>
var v = it.next().value;
// returns -1.0
v = it.next().value;
// returns -2.0
var bool = it.next().done;
// returns true
Notes
- If an iterated value is non-numeric (including
NaN
), the returned iterator returnsNaN
. If non-numeric iterated values are possible, you are advised to provide aniterator
which type checks and handles non-numeric values accordingly. - The length of the returned iterator is equal to the length of the shortest provided iterator. In other words, the returned iterator ends once one of the provided iterators ends.
- 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 uniform = require( '@stdlib/random-iter-uniform' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var iterMap2 = require( '@stdlib/math-iter-tools-map2' );
// Create seeded iterators for generating pseudorandom numbers:
var rand1 = randu({
'seed': 1234,
'iter': 10
});
var rand2 = uniform( -1.0, 1.0, {
'seed': 1234,
'iter': 10
});
// Create an iterator which consumes the pseudorandom number iterators:
var it = iterMap2( rand1, rand2, copysign );
// Perform manual iteration...
var r;
while ( true ) {
r = it.next();
if ( r.done ) {
break;
}
console.log( r.value );
}
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.