PHP RecursiveIteratorIterator::rewind() Method: Usage and Examples

Recursive iterators expose nested data one level at a time, while RecursiveIteratorIterator can flatten a hierarchy for traversal.

What Is RecursiveIteratorIterator::rewind in PHP?

Restarts traversal when supported by the wrapped iterator.

RecursiveIteratorIterator::rewind()

This operation does not accept method arguments.

Example 1: Understanding the Basic Behavior

<?php

$source = new RecursiveArrayIterator(["group" => ["first" => 1, "second" => 2], "status" => "active"]);
$iterator = new RecursiveIteratorIterator($source, RecursiveIteratorIterator::SELF_FIRST);
$iterator->rewind();
var_dump($iterator->current());

Output:

array(2) {
  ["first"]=>
  int(1)
  ["second"]=>
  int(2)
}

Explanation: Restarts traversal when supported by the wrapped iterator.

Example 2: Testing Another Case

<?php

$source = new RecursiveArrayIterator(["folder" => ["alpha" => 11, "beta" => 22], "state" => "pending"]);
$iterator = new RecursiveIteratorIterator($source, RecursiveIteratorIterator::SELF_FIRST);
$iterator->rewind();
var_dump($iterator->current());

Output:

array(2) {
  ["alpha"]=>
  int(11)
  ["beta"]=>
  int(22)
}

Explanation: Rewinding is not supported equally by every Traversable source, especially consumed generators.

Practical Example: Applying the Operation

<?php

$source = new RecursiveArrayIterator(["items" => ["red" => 100, "blue" => 200], "mode" => "ready"]);
$iterator = new RecursiveIteratorIterator($source, RecursiveIteratorIterator::SELF_FIRST);
$iterator->rewind();
var_dump($iterator->current());

Output:

array(2) {
  ["red"]=>
  int(100)
  ["blue"]=>
  int(200)
}

Explanation: Child operations are meaningful only for nested entries; traversal mode determines which keys and depths appear.

Important Behavior and Edge Cases

• Rewinding is not supported equally by every Traversable source, especially consumed generators.
• Child operations are meaningful only for nested entries; traversal mode determines which keys and depths appear.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Restarts traversal when supported by the wrapped iterator.
• Rewinding is not supported equally by every Traversable source, especially consumed generators.
• Child operations are meaningful only for nested entries; traversal mode determines which keys and depths appear.

The examples demonstrate where RecursiveIteratorIterator::rewind fits within nested iteration. Verify the relevant preconditions whenever you adapt the code to real data.