The NoRewindIterator class

(PHP 5 >= 5.1.0)

Introduction

This iterator cannot be rewound.

Class synopsis

NoRewindIterator extends IteratorIterator {

/* Methods */

public __construct ( Iterator $iterator )

public mixed current ( void )

public iterator getInnerIterator ( void )

public mixed key ( void )

public void next ( void )

public void rewind ( void )

public bool valid ( void )

/* Inherited methods */

public IteratorIterator::__construct ( Traversable $iterator )

public mixed IteratorIterator::current ( void )

public Traversable IteratorIterator::getInnerIterator ( void )

public scalar IteratorIterator::key ( void )

public void IteratorIterator::next ( void )

public void IteratorIterator::rewind ( void )

public bool IteratorIterator::valid ( void )

}

NoRewindIterator::__construct — Construct a NoRewindIterator
NoRewindIterator::current — Get the current value
NoRewindIterator::getInnerIterator — Get the inner iterator
NoRewindIterator::key — Get the current key
NoRewindIterator::next — Forward to the next element
NoRewindIterator::rewind — Prevents the rewind operation on the inner iterator.
NoRewindIterator::valid — Validates the iterator

Коментарии

Apr 26

Автор: Anonymous


As its name implies, NoRewindIterator doesn't invoke the "rewind" method when It reaches the end of the iterator.



Let's demonstrate it by two examles.



In this example the "rewind" method will be invoked after when the "foreache" reaches its end, so, we can repeat printing the same values as many times as we want:



<?PHP

$iterator = new ArrayIterator(['PHP', 'Python', 'Go']);



foreach ($iterator as $item) {

    echo $item.PHP_EOL;

}



foreach ($iterator as $item) {

    echo $item.PHP_EOL;

}

?>



By using the NoRewindIterator, the "rewind" won't be invoked, so, we can't do as we did in previous example:



<?PHP

$iterator = new ArrayIterator(['PHP', 'Python', 'Go']);

$iterator = new NoRewindIterator($iterator);



foreach ($iterator as $item) {

    echo $item.PHP_EOL;

}



// doesn't do anything

foreach ($iterator as $item) {

    echo $item.PHP_EOL;

}



?>