Класс ArrayIterator

(PHP 5, PHP 7, PHP 8)

Введение

Класс делает возможным удаление элементов и изменение ключей или значений при итерации по массивам или объектам.

Для многократного перебора одного и того же массива создают экземпляр класса ArrayObject и разрешают ему создавать экземпляры объектов ArrayIterator, которые ссылаются на него либо через конструкцию foreach, либо путём вызова его метода getIterator() вручную.

Обзор классов

class ArrayIterator implements SeekableIterator, ArrayAccess, Serializable, Countable {
/* Константы */
public const int STD_PROP_LIST;
public const int ARRAY_AS_PROPS;
/* Методы */
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 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
}

Предопределённые константы

Флаги ArrayIterator

ArrayIterator::STD_PROP_LIST

Свойства объекта ведут себя так же, как при доступе к ним как к элементам списка (var_dump, foreach и т. д.).

ArrayIterator::ARRAY_AS_PROPS

Класс открывает доступ к элементам как к свойствам объекта при чтении и записи.

Содержание

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User Contributed Notes 4 notes

up
50
Venelin Vulkov
15 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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