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    The ArrayIterator class

    (PHP 5, PHP 7, PHP 8)

    Introduction

    Allows the removal of elements, and the modification of keys or values while iterating over arrays or objects.

    To iterate the same array more than once, it is recommended to instantiate ArrayObject and use the ArrayIterator instance either implicitly created when using foreach to iterate over the array stored internally, or create one by calling the ArrayObject::getIterator() method manually.

    Class synopsis

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

    Predefined Constants

    ArrayIterator Flags

    ArrayIterator::STD_PROP_LIST

    Properties of the object have their normal functionality when accessed as list (var_dump(), foreach, etc.).

    ArrayIterator::ARRAY_AS_PROPS

    Entries can be accessed as properties (read and write).

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    User Contributed Notes 4 notes

    up
    50
    Venelin Vulkov
    16 years ago
    Another fine Iterator from php . You can use it especially when you have to iterate over objects

    <?php
    $fruits     = array(
    "apple" => "yummy",
    "orange" => "ah ya, nice",
    "grape" => "wow, I love it!",
    "plum" => "nah, not me"
    );
    $obj = new ArrayObject( $fruits );
    $it = $obj->getIterator();

    // How many items are we iterating over?

    echo "Iterating over: " . $obj->count() . " values\n";

    // Iterate over the values in the ArrayObject:
    while( $it->valid() )
    {
    echo     $it->key() . "=" . $it->current() . "\n";
    $it->next();
    }

    // The good thing here is that it can be iterated with foreach loop

    foreach ($it as $key=>$val)
    echo     $key.":".$val."\n";

    /* Outputs something like */

    Iterating over: 4 values
    apple    =yummy
    orange    =ah ya, nice
    grape    =wow, I love it!
    plum=nah, not me

    ?>

    Regards.
    up
    18
    Relakuyae
    13 years ago
    Need a callback on an iterated value, but don't have PHP 5.4+? This makes is stupid easy:

    <?php
    class ArrayCallbackIterator extends ArrayIterator {
    private     $callback;
    public function     __construct($value, $callback) {
    parent::__construct($value);
    $this->callback = $callback;
    }

    public function     current() {
    $value = parent::current();
    return     call_user_func($this->callback, $value);
    }
    }
    ?>

    You can use it pretty much exactly as the Array Iterator:

    <?php
    $iterator1     = new ArrayCallbackIterator($valueList, "callback_function");
    $iterator2 = new ArrayCallbackIterator($valueList, array($object, "callback_class_method"));
    ?>
    up
    10
    Sean Burlington
    15 years ago
    and to iterate recursively use the (sparsely documented) RecursiveArrayIterator

    <?php

    $fruits     = array(
    "apple" => "yummy",
    "orange" => "ah ya, nice",
    "grape" => "wow, I love it!",
    "plum" => "nah, not me"
    );

    $veg = array("potato" => "chips", "carrot" => "soup");
    $grocery = array($fruits, $veg);
    $obj = new ArrayObject( $grocery );

    $it = new RecursiveIteratorIterator( new RecursiveArrayIterator($grocery));

    foreach (    $it as $key=>$val)
    echo     $key.":".$val."\n";

    ?>

    Output
    --------
    apple:yummy
    orange:ah ya, nice
    grape:wow, I love it!
    plum:nah, not me
    potato:chips
    carrot:soup
    up
    1
    butesa at freenet dot de
    2 years ago
    The documentation states "This iterator allows to unset and modify values and keys while iterating over Arrays and Objects". But if you pass an array to the constructor, the iterator works with a copy of that array, so the modifications will not be written back to that initial array. ArrayObject behaves the same way.

    If you want an iterator that writes back to the array, you can use this function:

    <?php
    function &getArrayIterator(array &$a): Iterator {
    foreach (    $a as $k => &$v) {
    yield     $k => $v;
    }
    }
    ?>

    Usage:

    <?php
    $array     = [1 => 'a', 2 => 'b'];

    $iterator = getArrayIterator($array);
    foreach (    $iterator as &$value) {
    $value .= 'x';
    }

    //array(2) {
    // [1]=>
    // string(2) "ax"
    // [2]=>
    // &string(2) "bx"
    //}
    //object(Generator)#4 (0) {
    //}
    var_dump($array);
    var_dump($iterator);

    ?>

    Comparison with plain array, ArrayIterator and ArrayObject:

    <?php
    $array1     = [1 => 'a', 2 => 'b'];
    $array2 = [1 => 'a', 2 => 'b'];
    $array3 = [1 => 'a', 2 => 'b'];

    foreach (    $array1 as &$value) {
    $value .= 'x';
    }

    $iterator2 = new ArrayIterator($array2);
    foreach (    $iterator2 as &$value) {
    $value .= 'x';
    }

    $iterator3 = new ArrayObject($array3);
    foreach (    $iterator3 as &$value) {
    $value .= 'x';
    }

    //array(2) {
    // [1]=>
    // string(2) "ax"
    // [2]=>
    // string(2) "bx"
    //}
    var_dump($array1);

    //array(2) {
    // [1]=>
    // string(1) "a"
    // [2]=>
    // string(1) "b"
    //}
    //object(ArrayIterator)#1 (1) {
    // ["storage":"ArrayIterator":private]=>
    // array(2) {
    // [1]=>
    // string(2) "ax"
    // [2]=>
    // string(2) "bx"
    // }
    //}
    var_dump($array2);
    var_dump($iterator2);

    //array(2) {
    // [1]=>
    // string(1) "a"
    // [2]=>
    // string(1) "b"
    //}
    //object(ArrayObject)#2 (1) {
    // ["storage":"ArrayObject":private]=>
    // array(2) {
    // [1]=>
    // string(2) "ax"
    // [2]=>
    // string(2) "bx"
    // }
    //}
    var_dump($array3);
    var_dump($iterator3);
    ?>
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