iterStrided

Create an iterator which steps by a specified amount.

Usage

var iterStrided = require( '@stdlib/iter/strided' );

iterStrided( iterator, stride[, offset[, eager]] )

Returns an iterator which steps by a specified amount.

var array2iterator = require( '@stdlib/array/to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 2 );
// returns <Object>

var r = it.next().value;
// returns 1

r = it.next().value;
// returns 3

r = it.next().value;
// returns 5

// ...

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 a done property having a boolean 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.

To skip the first N values of a provided iterator, provide an offset argument.

var array2iterator = require( '@stdlib/array/to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 2, 1 );
// returns <Object>

var r = it.next().value;
// returns 2

r = it.next().value;
// returns 4

r = it.next().value;
// returns 6

// ...

By default, the returned iterator defers consuming the first N input iterator values until the first value of the returned iterator is consumed. To eagerly advance the input iterator, set the eager argument to true.

var array2iterator = require( '@stdlib/array/to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 1, 4, true );
// returns <Object>

var r = it.next().value;
// returns 5

r = it.next().value;
// returns 6

r = it.next().value;
// returns 7

// ...

Notes

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 iterStrided = require( '@stdlib/iter/strided' );

// Create a seeded iterator for generating pseudorandom numbers:
var rand = randu({
    'seed': 1234,
    'iter': 10
});

// Create an iterator which returns every other random number:
var it = iterStrided( rand, 2 );

// Perform manual iteration...
var r;
while ( true ) {
    r = it.next();
    if ( r.done ) {
        break;
    }
    console.log( r.value );
}