La interfaz IteratorAggregate

(PHP 5 >= 5.0.0, PHP 7)

Introducción

Para crear una interfaz externa Iterator.

Sinopsis de la Interfaz

IteratorAggregate extends Traversable {
/* Métodos */
abstract public Traversable getIterator ( void )
}

Ejemplo #1 Uso básico

<?php
class myData implements IteratorAggregate {
    public 
$property1 "Public property one";
    public 
$property2 "Public property two";
    public 
$property3 "Public property three";

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

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

$obj = new myData;

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

El resultado del ejemplo sería algo similar a:

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"

Tabla de contenidos

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User Contributed Notes 4 notes

up
16
Tab Atkins
5 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
Lubaev.K
4 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!
up
2
trumbull dot j at gmail dot com
7 months 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
-12
ribeirocfb at gmail dot com
2 years ago
Example of the Iterator Pattern

<?php

namespace DesignPaterns;

class
BookCollection implements \IteratorAggregate
{
    private
$a_titles = array();

    public function
getIterator()
    {
        return new
BookIterator($this);
    }

    public function
addTitle($string)
    {
       
$this->a_titles[] = $string;
    }

    public function
getTitle($key)
    {
        if (isset(
$this->a_titles[$key])){
            return
$this->a_titles[$key];
        }
        return
null;
    }

    public function
is_empty()
    {
        return empty(
$a_titles);
    }
}

<?
php

namespace DesignPaterns;

class
BookIterator implements \Iterator
{
    private
$i_position = 0;
    private
$booksCollection;

    public function
__construct(BookCollection $booksCollection)
    {
       
$this->booksCollection = $booksCollection;
    }

    public function
current()
    {
        return
$this->booksCollection->getTitle($this->i_position);
    }

    public function
key()
    {
        return
$this->i_position;
    }

    public function
next()
    {
       
$this->i_position++;
    }

    public function
rewind()
    {
       
$this->i_position = 0;
    }

    public function
valid()
    {
        return !
is_null($this->booksCollection->getTitle($this->i_position));
    }
}

<?
php require 'vendor/autoload.php';

use
DesignPaterns\BookCollection;

$booksCollection = new BookCollection();
$booksCollection->addTitle('Design Patterns');
$booksCollection->addTitle('PHP7 is the best');
$booksCollection->addTitle('Laravel Rules');
$booksCollection->addTitle('DHH Rules');

foreach(
$booksCollection as $book){
   
var_dump($book);
}

/* === Output ===
* string(15) "Design Patterns"
* string(16) "PHP7 is the best"
* string(13) "Laravel Rules"
* string(9) "DHH Rules"
*/
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