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    The ArrayIterator class

    (PHP 5, PHP 7)

    소개

    This iterator allows to unset and modify values and keys while iterating over Arrays and Objects.

    When you want to iterate over the same array multiple times you need to instantiate ArrayObject and let it create ArrayIterator instances that refer to it either by using foreach or by calling its getIterator() method manually.

    클래스 개요

    ArrayIterator implements ArrayAccess , SeekableIterator , Countable , Serializable {
    /* 메소드 */
    public void append ( mixed $value )
    public void asort ( void )
    public __construct ([ mixed $array = array() [, int $flags = 0 ]] )
    public int count ( void )
    public mixed current ( void )
    public array getArrayCopy ( void )
    public void getFlags ( void )
    public mixed key ( void )
    public void ksort ( void )
    public void natcasesort ( void )
    public void natsort ( void )
    public void next ( void )
    public void offsetExists ( string $index )
    public mixed offsetGet ( string $index )
    public void offsetSet ( string $index , string $newval )
    public void offsetUnset ( string $index )
    public void rewind ( void )
    public void seek ( int $position )
    public string serialize ( void )
    public void setFlags ( string $flags )
    public void uasort ( string $cmp_function )
    public void uksort ( string $cmp_function )
    public string unserialize ( string $serialized )
    public bool valid ( void )
    }

    Table of Contents

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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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