iterUnique

Create an iterator which returns unique values.

Usage

var iterUnique = require( '@stdlib/iter/unique' );

iterUnique( iterator )

Returns an iterator which returns unique values.

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

var it = iterUnique( array2iterator( [ 2, 1, 1, 2, 4, 3, 4, 3 ] ) );
// returns <Object>

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

v = it.next().value;
// returns 1

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

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

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 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.

Notes

  • Value "uniqueness" is determined according to strict equality.
  • A returned iterator internally buffers unique values and, thus, has O(N) memory requirements.
  • If an environment supports Symbol.iterator and a provided iterator is iterable, the returned iterator is iterable.

Examples

var discreteUniform = require( '@stdlib/random/iter/discrete-uniform' );
var iterUnique = require( '@stdlib/iter/unique' );

// Create a seeded iterator which can generate 1000 pseudorandom numbers:
var rand = discreteUniform( 1, 10, {
    'seed': 1234,
    'iter': 1000
});

// Create an iterator which returns unique values:
var it = iterUnique( rand );

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

See Also

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