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Create an iterator which rejects the values of another iterator according to a predicate function.
npm install @stdlib/iter-reject
var iterReject = require( '@stdlib/iter-reject' );
Returns an iterator which rejects the values of another iterator
according to a predicate
function.
var array2iterator = require( '@stdlib/array-to-iterator' );
function predicate( v ) {
return ( v > 2 );
}
var it = iterReject( array2iterator( [ 1, 3, 2, 4 ] ), predicate );
// 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.
The predicate
function is provided two arguments:
-
value
: iterated value -
index
: iteration index (zero-based)
var array2iterator = require( '@stdlib/array-to-iterator' );
function predicate( v, i ) {
return ( i >= 2 );
}
var it = iterReject( array2iterator( [ 3, 4, 1, 2 ] ), predicate );
// returns <Object>
var v = it.next().value;
// returns 3
v = it.next().value;
// returns 4
var bool = it.next().done;
// returns true
To set the predicate
function execution context, provide a thisArg
.
var array2iterator = require( '@stdlib/array-to-iterator' );
function predicate( v ) {
this.count += 1;
return ( v > 10 );
}
var ctx = {
'count': 0
};
var it = iterReject( array2iterator( [ 1, 2, 3, 4 ] ), predicate, ctx );
// returns <Object>
var v = it.next().value;
// returns 1
v = it.next().value;
// returns 2
v = it.next().value;
// returns 3
var count = ctx.count;
// returns 3
var randu = require( '@stdlib/random-iter-randu' );
var iterReject = require( '@stdlib/iter-reject' );
function predicate( v ) {
return ( v > 0.5 );
}
// Create a seeded iterator for generating pseudorandom numbers:
var rand = randu({
'seed': 1234,
'iter': 20
});
// Create an iterator which filters the generated numbers:
var it = iterReject( rand, predicate );
// Perform manual iteration...
var r;
while ( true ) {
r = it.next();
if ( r.done ) {
break;
}
console.log( r.value );
}
-
@stdlib/iter-filter
: create an iterator which filters the values of another iterator according to a predicate function. -
@stdlib/iter-map
: create an iterator which invokes a function for each iterated value.
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.
See LICENSE.
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