PHP - Manual: ArrayIterator

2024-11-23

ArrayIterator 类

(PHP 5, PHP 7, PHP 8)

简介

这个迭代器允许在遍历数组和对象时删除和更新值与键。

当你想多次遍历相同数组时你需要实例化 ArrayObject，然后让这个实例创建一个 ArrayIterator 实例。当你想遍历相同数组时多次你需要实例 ArrayObject 并且让这个实例创建一个 ArrayIterator 实例，然后使用 foreach 或者手动调用 getIterator() 方法。

类摘要

class ArrayIterator implements SeekableIterator, ArrayAccess, Serializable, Countable {

/* 常量 */

const int STD_PROP_LIST = 1;

const int ARRAY_AS_PROPS = 2;

/* 方法 */

public __construct(array|object $array = [], int $flags = 0)

public append(mixed $value): void

public asort(int $flags = SORT_REGULAR): bool

public count(): int

public current(): mixed

public getArrayCopy(): array

public getFlags(): int

public key(): string|int|null

public ksort(int $flags = SORT_REGULAR): bool

public natcasesort(): bool

public natsort(): bool

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): bool

public uksort(callable $callback): bool

public unserialize(string $data): void

public valid(): bool

}

预定义常量

ArrayIterator 标记

ArrayIterator::STD_PROP_LIST: Properties of the object have their normal functionality when accessed as list (var_dump, foreach, etc.).
ArrayIterator::ARRAY_AS_PROPS: 可以通过属性访问条目（读写都支持）。

ArrayIterator::append — Append an element
ArrayIterator::asort — Sort entries by values
ArrayIterator::__construct — Construct an ArrayIterator
ArrayIterator::count — Count elements
ArrayIterator::current — Return current array entry
ArrayIterator::getArrayCopy — Get array copy
ArrayIterator::getFlags — Get behavior flags
ArrayIterator::key — Return current array key
ArrayIterator::ksort — Sort entries by keys
ArrayIterator::natcasesort — Sort entries naturally, case insensitive
ArrayIterator::natsort — Sort entries naturally
ArrayIterator::next — Move to next entry
ArrayIterator::offsetExists — Check if offset exists
ArrayIterator::offsetGet — Get value for an offset
ArrayIterator::offsetSet — Set value for an offset
ArrayIterator::offsetUnset — Unset value for an offset
ArrayIterator::rewind — Rewind array back to the start
ArrayIterator::seek — Seek to position
ArrayIterator::serialize — Serialize
ArrayIterator::setFlags — Set behaviour flags
ArrayIterator::uasort — Sort with a user-defined comparison function and maintain index association
ArrayIterator::uksort — Sort by keys using a user-defined comparison function
ArrayIterator::unserialize — Unserialize
ArrayIterator::valid — Check whether array contains more entries

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User Contributed Notes 7 notes

down

Venelin Vulkov ¶

13 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.

down

Relakuyae ¶

10 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"));

?>

down

Sean Burlington ¶

13 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

down

mail at markuszeller dot com ¶

1 year ago


I recommend using ArrayIterator() only in the IteratorAggregate interface on behalf of memory usage.
When not used in that context, the array will be copied on creating a new ArrayIterator().

<?php
class Data implements IteratorAggregate
{
    private array $array = [];

    public function __construct()
    {
        for ($i = 0; $i < 1e5; $i++) $this->array[] = true;
    }

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

$data1 = new Data();
echo memory_get_usage(), PHP_EOL;
// 4610240

foreach($data1 as $data) {}
echo memory_get_usage(), PHP_EOL;
// 4610240

foreach($data1 as $data) {}
echo memory_get_usage(), PHP_EOL;
// 4610240
?>

Memory usage still stay the same.
Now create it without the IteratorAggregate interface.

<?php
$agg = [];
for ($i = 0; $i < 1e5; $i++) $agg[] = true;
echo memory_get_usage(), PHP_EOL;
// 8808720

$iterator1 = new ArrayIterator($agg);
echo memory_get_usage(), PHP_EOL;
// 13007328

$iterator2 = new ArrayIterator($agg);
echo memory_get_usage(), PHP_EOL;
// 17205936
?>

down

shaman_master at list dot ru ¶

2 years ago


If you want something like `ArrayCallbackIterator` by Relakuyae https://www.php.net/manual/ru/class.arrayiterator.php#106231 , use function `iterator_apply`.

down

-9

daniel dot rutkoski at gmail dot com ¶

6 years ago


<?php
class PrintArray
{
    private $code = null;

    function __construct ($val)
    {
        $this->code = $val;
        $this->_print();
    }
    
    private function arrayIterator($val, $grau)
    {
        $grau++;
        $arr = new \ArrayIterator($val);
        while ($arr->valid())
        {
            if(is_array($arr->current()))
            {
                $this->arrayIterator($arr->current(), $grau);
            }
            else
            {
                $this->code .= str_repeat(" ", (4 * $grau)) . $arr->key() . " : " . $arr->current() . PHP_EOL;
            }
            $arr->next();
        }
    }
    
    private function _print() 
    {
        if (is_array($this->code))
        {
            $arr = new \ArrayIterator($this->code);
            $this->code = 'array(' . PHP_EOL;
            while ($arr->valid())
            {
                if(is_array($arr->current()))
                {
                    $this->arrayIterator($arr->current(), 0);
                }
                else
                {
                    $this->code .= $arr->key() . " : " . $arr->current() . "\n";
                }
                $arr->next();
            }
            $this->code .= ')';
        }
        return $this;
    }
    
    public function getVal ()
    {
        return $this->code;
    }
}

$arr = array(
    array(
        'ok' => 1, array(9,7,5,9,'a','b'=>array(1,2)),
        'error' => 2, array('h','u','o')
    )
    , 'array'
);
$pArray = new PrintArray($arr);
var_dump($pArray->getVal());

down

-28

foobuilder at gmail dot com ¶

11 years ago


Unsetting all keys of an ArrayItem within foreach will always leave the second key: 

<?php
$items = new ArrayObject(range(0, 9)); 

while (list($k, $v) = each($items)) {
    unset($items[$k]); 
}

print_r($items); 

//  ArrayIterator Object
//  (
//      [storage:ArrayIterator:private] => Array
//          (
//              [1] => 1
//          )
//  )
?>

I'm not sure if this is a bug as unsetting keys within foreach is usually a bad idea to begin with (use while instead), but it's something to be aware of.

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官方地址：https://www.php.net/manual/en/class.arrayiterator.php

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PHP官方手册 - 互联网笔记

ArrayIterator 类

简介

类摘要

预定义常量

ArrayIterator 标记

目录

User Contributed Notes 7 notes