The RecursiveArrayIterator class

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    Introduction

    This iterator allows for unsetting and modifying values and keys while iterating over arrays and objects, in the same way as the ArrayIterator. Additionally, it is possible to iterate over the current iterator entry.

    Class synopsis

    class RecursiveArrayIterator extends ArrayIterator implements RecursiveIterator {
    /* Inherited constants */
    public const int ArrayIterator::STD_PROP_LIST;
    public const int ArrayIterator::ARRAY_AS_PROPS;
    /* Constants */
    public const int CHILD_ARRAYS_ONLY;
    /* Methods */
    public getChildren(): ?RecursiveArrayIterator
    public hasChildren(): bool
    /* Inherited methods */
    public ArrayIterator::__construct(array|object $array = [], int $flags = 0)
    public ArrayIterator::append(mixed $value): void
    public ArrayIterator::asort(int $flags = SORT_REGULAR): true
    public ArrayIterator::count(): int
    public ArrayIterator::current(): mixed
    public ArrayIterator::getArrayCopy(): array
    public ArrayIterator::getFlags(): int
    public ArrayIterator::key(): string|int|null
    public ArrayIterator::ksort(int $flags = SORT_REGULAR): true
    public ArrayIterator::natcasesort(): true
    public ArrayIterator::natsort(): true
    public ArrayIterator::next(): void
    public ArrayIterator::offsetExists(mixed $key): bool
    public ArrayIterator::offsetGet(mixed $key): mixed
    public ArrayIterator::offsetSet(mixed $key, mixed $value): void
    public ArrayIterator::offsetUnset(mixed $key): void
    public ArrayIterator::rewind(): void
    public ArrayIterator::seek(int $offset): void
    public ArrayIterator::serialize(): string
    public ArrayIterator::setFlags(int $flags): void
    public ArrayIterator::uasort(callable $callback): true
    public ArrayIterator::uksort(callable $callback): true
    public ArrayIterator::unserialize(string $data): void
    public ArrayIterator::valid(): bool
    }

    Predefined Constants

    RecursiveArrayIterator Flags

    RecursiveArrayIterator::CHILD_ARRAYS_ONLY

    Treat only arrays (not objects) as having children for recursive iteration.

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    User Contributed Notes 4 notes

    up
    18
    c dot 1 at smithies dot org
    13 years ago
    If you are iterating over a multi-dimensional array of objects, you may be tempted to use a RecursiveArrayIterator within a RecursiveIteratorIterator. You are likely to get baffling results if you do. That is because RecursiveArrayIterator treats all objects as having children, and tries to recurse into them. But if you are interested in having your RecursiveIteratorIterator return the objects in your multi-dimensional array, then you don't want the default setting LEAVES_ONLY, because no object can be a leaf (= has no children).

    The solution is to extend the RecursiveArrayIterator class and override the hasChildren method appropriately. Something like the following might be suitable:

    <?php
    class RecursiveArrayOnlyIterator extends RecursiveArrayIterator {
    public function     hasChildren() {
    return     is_array($this->current());
    }
    }
    ?>
    Of course, this simple example will not recurse into ArrayObjects either!
    up
    16
    mccarthy dot richard at gmail dot com
    13 years ago
    Using the RecursiveArrayIterator to traverse an unknown amount of sub arrays within the outer array. Note: This functionality is already provided by using the RecursiveIteratorIterator but is useful in understanding how to use the iterator when using for the first time as all the terminology does get rather confusing at first sight of SPL!

    <?php
    $myArray     = array(
    0 => 'a',
    1 => array('subA','subB',array(0 => 'subsubA', 1 => 'subsubB', 2 => array(0 => 'deepA', 1 => 'deepB'))),
    2 => 'b',
    3 => array('subA','subB','subC'),
    4 => 'c'
    );

    $iterator = new RecursiveArrayIterator($myArray);
    iterator_apply($iterator, 'traverseStructure', array($iterator));

    function     traverseStructure($iterator) {

    while (     $iterator -> valid() ) {

    if (     $iterator -> hasChildren() ) {

    traverseStructure($iterator -> getChildren());

    }
    else {
    echo     $iterator -> key() . ' : ' . $iterator -> current() .PHP_EOL;
    }

    $iterator -> next();
    }
    }
    ?>

    The output from which is:
    0 : a
    0 : subA
    1 : subB
    0 : subsubA
    1 : subsubB
    0 : deepA
    1 : deepB
    2 : b
    0 : subA
    1 : subB
    2 : subC
    4 : c
    up
    8
    lemoinem dot remove at me dot mlemoine dot name
    10 years ago
    The RecursiveArrayOnlyIterator behaviour c dot 1 at smithies dot org presented can also be achieved using the (undocumented) flag RecursiveArrayIterator::CHILD_ARRAYS_ONLY (https://github.com/php/php-src/blob/master/ext/spl/spl_array.c#L1970 and https://github.com/php/php-src/blob/master/ext/spl/spl_array.c#L1620)
    up
    4
    Edgar
    2 years ago
    <?php
    $array     = [
    'A','B',
    'C'=>[
    'D','E',
    'F'=>['G','H']
    ],
    'I','J'
    ];

    $iterator = new RecursiveArrayIterator($array);

    foreach(    $iterator as $key=>$value)
    {
    echo     $key,':', $value,'<br>';
    }

    /**
    Output
    0:A
    1:B
    C:Array
    2:I
    3:J
    */

    //-------------
    //Recursive...

    $array = [
    'A','B',
    'C'=>[
    'D','E',
    'F'=>['G','H']
    ],
    'I','J'
    ];

    $it = new RecursiveArrayIterator($array);
    $iterator = new RecursiveIteratorIterator($it);

    foreach(    $iterator as $key=>$value)
    {
    echo     $key,':', $value,'<br>';
    }

    /**
    Output
    0:A
    1:B
    0:D
    1:E
    0:G
    1:H
    2:I
    3:J
    */

    ?>
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