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    The IteratorAggregate interface

    (PHP 5, PHP 7, PHP 8)

    Introduction

    Interface to create an external Iterator.

    Interface synopsis

    interface IteratorAggregate extends Traversable {
    /* Methods */
    public getIterator(): Traversable
    }

    Examples

    Example #1 Basic usage

    <?php

    class myData implements IteratorAggregate
    {
    public     $property1 = "Public property one";
    public     $property2 = "Public property two";
    public     $property3 = "Public property three";
    public     $property4 = "";

    public function     __construct()
    {
    $this->property4 = "last property";
    }

    public function     getIterator(): Traversable
    {
    return new     ArrayIterator($this);
    }
    }

    $obj = new myData();

    foreach (    $obj as $key => $value) {
    var_dump($key, $value);
    echo     "\n";
    }

    ?>

    The above example will output something similar to:

    string(9) "property1"
string(19) "Public property one"

string(9) "property2"
string(19) "Public property two"

string(9) "property3"
string(21) "Public property three"

string(9) "property4"
string(13) "last property"

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    User Contributed Notes 4 notes

    up
    33
    trumbull dot j at gmail dot com ΒΆ
    8 years ago
    It might seem obvious, but you can return a compiled generator from your IteratorAggregate::getIterator() implementation.

    <?php
    class Collection implements IteratorAggregate
    {
    private     $items = [];

    public function     __construct($items = [])
    {
    $this->items = $items;
    }

    public function     getIterator()
    {
    return (function () {
    while(list(    $key, $val) = each($this->items)) {
    yield     $key => $val;
    }
    })();
    }
    }

    $data = [ 'A', 'B', 'C', 'D' ];
    $collection = new Collection($data);

    foreach (    $collection as $key => $val) {
    echo     sprintf("[%s] => %s\n", $key, $val);
    }
    ?>
    up
    22
    Tab Atkins ΒΆ
    13 years ago
    Note that, at least as of 5.3, you still aren't allowed to return a normal Array from getIterator().

    In some places, the docs wrap the array into an ArrayObject and return that. DON'T DO IT. ArrayObject drops any empty-string keys on the floor when you iterate over it (again, at least as of 5.3).

    Use ArrayIterator instead. I wouldn't be surprised if it didn't have its own set of wonderful bugs, but at the very least it works correctly when you use it with this method.
    up
    10
    Martin Speer ΒΆ
    6 years ago
    You can use yield from in getIterator in recent PHP 7 versions:

    <?php

    class Example implements \IteratorAggregate
    {
    protected     $data = [];

    public function     __construct(array $data)
    {
    $this->data = $data;
    }

    public function     getIterator()
    {
    yield from     $this->data;
    }
    }

    $test = new Example([1, 2, 3]);

    foreach (    $test as $node) {
    echo     $test, PHP_EOL;
    }

    /*
    * Outputs:
    *
    * 1
    * 2
    * 3
    */     ?>
    up
    13
    Lubaev.K ΒΆ
    12 years ago
    <?php
    // IteratorAggregate
    // Create indexed and associative arrays.

    class myData implements IteratorAggregate {

    private     $array = [];
    const     TYPE_INDEXED = 1;
    const     TYPE_ASSOCIATIVE = 2;

    public function     __construct( array $data, $type = self::TYPE_INDEXED ) {
    reset($data);
    while( list(    $k, $v) = each($data) ) {
    $type == self::TYPE_INDEXED ?
    $this->array[] = $v :
    $this->array[$k] = $v;
    }
    }

    public function     getIterator() {
    return new     ArrayIterator($this->array);
    }

    }

    $obj = new myData(['one'=>'php','javascript','three'=>'c#','java',], /*TYPE 1 or 2*/ );

    foreach(    $obj as $key => $value) {
    var_dump($key, $value);
    echo     PHP_EOL;
    }

    // if TYPE == 1
    #int(0)
    #string(3) "php"
    #int(1)
    #string(10) "javascript"
    #int(2)
    #string(2) "c#"
    #int(3)
    #string(4) "java"

    // if TYPE == 2
    #string(3) "one"
    #string(3) "php"
    #int(0)
    #string(10) "javascript"
    #string(5) "three"
    #string(2) "c#"
    #int(1)
    #string(4) "java"
    ?>

    Good luck!
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