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
    29
    trumbull dot j at gmail dot com
    7 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
    12 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
    11
    Martin Speer
    5 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
    15
    Lubaev.K
    11 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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