iterReject
Create an iterator which rejects the values of another iterator according to a predicate function.
Usage
var iterReject = require( '@stdlib/iter/reject' );
iterReject( iterator, predicate[, thisArg] )
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 valueindex
: 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
Notes
Examples
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 );
}