IteratorAggregate 接口

    (PHP 5, PHP 7, PHP 8)

    简介

    用于创建外部迭代器的接口。

    接口概要

    interface IteratorAggregate extends Traversable {
    /* 方法 */
    public getIterator(): Traversable
    }

    示例

    示例 #1 基本用法

    <?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";
    }

    ?>

    上面的例子将输出类似于

    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"

    目录

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    ＋添加说明

    用户贡献的说明 5 个说明

    28
    trumbull dot j at gmail dot com
    7 年前
    这可能看起来很明显，但你可以从你的 IteratorAggregate::getIterator() 实现中返回一个已编译的生成器。

    <?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);
    }
    ?>
    22
    Tab Atkins
    12 年前
    请注意，至少在 5.3 版本中，你仍然不允许从 getIterator() 返回一个普通的数组。

    在某些地方，文档将数组封装到 ArrayObject 中并返回它。不要这样做。ArrayObject 在你迭代它时会丢弃任何空字符串键（同样，至少在 5.3 版本中）。

    请改用 ArrayIterator。我不会感到惊讶，如果它没有它自己的一套奇妙的错误，但至少它在使用此方法时能够正常工作。
    10
    Martin Speer
    5 年前
    您可以在最近的 PHP 7 版本的 getIterator 中使用 yield from

    <?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;
    }

    /*
    * 输出：
    *
    * 1
    * 2
    * 3
    */     ?>
    14
    Lubaev.K
    11 年前
    <?php
    // IteratorAggregate
    // 创建索引和关联数组。

    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"
    ?>

    祝你好运！
    -17
    ribeirocfb at gmail dot com
    8 年前
    迭代器模式示例

    <?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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