使用PHP的迭代器嵌套列表?

I'm trying to display this kind of array:

我想展示这种数组:

$nodes = array(

  1 => array(
         'title'    => 'NodeLvl1',
         'children' => array(),
       ),    
  2 => array(
         'title'    => 'NodeLvl1',
         'children' => array(        
                         1 => array(
                                'title'    => 'NodeLvl2',
                                'children' => array(),
                             ),    
                         2 => array(
                                'title'    => 'NodeLvl2',
                                'children' => array(


                                   1 => array(
                                          'title'    => 'NodeLvl3',
                                          'children' => array(),
                                       ),


                                   2 => array(
                                          'title'    => 'NodeLvl3',
                                          'children' => array(),
                                       ),    
                                ),
                              ),    

                       ),
       ),

  3 => array(
         'title'    => 'NodeLvl1',
         'children' => array(),
       ),    
);

like this:

是这样的:

<ul>
  <li>
    NodeLvl1
  </li>
  <li>
    NodeLvl1
      <ul>
        <li>NodeLv2</li>
         ...

      </ul>
  </li>
  ...

Basically a nested list taking into account the "children" property. So far I've come up with this:

基本上是考虑到“子”属性的嵌套列表。到目前为止，我想到了

class It extends RecursiveIteratorIterator{

  protected
    $tab    = "\t";

  public function beginChildren(){

    if(count($this->getInnerIterator()) == 0)
      return;

    echo str_repeat($this->tab, $this->getDepth())."<ul>\n";
  }

  public function endChildren(){


    if(count($this->getInnerIterator()) == 0)
      return;

    echo str_repeat($this->tab, $this->getDepth())."\n</ul>";
  }

  public function nextElement(){
    echo str_repeat($this->tab, $this->getDepth() + 1).'<li>';
  }

}

$it = new It(new RecursiveArrayIterator($nodes));

foreach($it as $key => $item)
  echo $item;

Which doesn't work quite right: I get each item wrapped between <ul>s and I don't know how can I close <li>s...

这不是很正确:我把每件东西都包装在

s之间，我不知道如何关闭
• s…

• 年代…

Any ideas on how to make this work? Also is it possible to get all the array properties (the actual element), instead of just the "title" property inside my foreach() loop? And can this be done with objects instead of arrays?

有什么办法可以让它工作吗?还有，是否可以获取所有的数组属性(实际的元素)，而不是在foreach()循环中只获取“title”属性?这能通过对象而不是数组来实现吗?

5 个解决方案

#1

You can use RecursiveCachingIterator to do what you want. Here is an example, (source: https://github.com/cballou/PHP-SPL-Iterator-Interface-Examples/blob/master/recursive-caching-iterator.php)

您可以使用RecursiveCachingIterator来执行所需的操作。下面是一个示例(源代码:https://github.com/cballou/php - spl -iterator - interface - examples/blob/master/recursis-caching-iterator.php)

<?php
// example navigation array
$nav = array(
    'Home' => '/home',
    'Fake' => array(
        'Double Fake' => array(
            'Nested Double Fake' => '/fake/double/nested',
            'Doubly Nested Double Fake' => '/fake/double/doubly'
        ),
        'Triple Fake' => '/fake/tripe'
    ),
    'Products' => array(
        'Product 1' => '/products/1',
        'Product 2' => '/products/2',
        'Product 3' => '/products/3',
        'Nested Product' => array(
            'Nested 1' => '/products/nested/1',
            'Nested 2' => '/products/nested/2'
        )
    ),
    'Company' => '/company',
    'Privacy Policy' => '/privacy-policy'
);

class NavBuilder extends RecursiveIteratorIterator {

    // stores the previous depth
    private $_depth = 0;

    // stores the current iteration's depth
    private $_curDepth = 0;

    // store the iterator
    protected $_it;

    /**
     * Constructor.
     *
     * @access  public
     * @param   Traversable $it
     * @param   int         $mode
     * @param   int         $flags
     */
    public function __construct(Traversable $it, $mode = RecursiveIteratorIterator::SELF_FIRST, $flags = 0)
    {
        parent::__construct($it, $mode, $flags);

        // store the caching iterator
        $this->_it = $it;
    }

    /**
     * Override the return values.
     *
     * @access  public
     */
    public function current()
    {
        // the return output string
        $output = '';

        // set the current depth
        $this->_curDepth = parent::getDepth();

        // store the difference in depths
        $diff = abs($this->_curDepth - $this->_depth);

        // get the name and url of the nav item
        $name = parent::key();
        $url = parent::current();

        // close previous nested levels
        if ($this->_curDepth < $this->_depth) {
            $output .= str_repeat('</ul></li>', $diff);
        }

        // check if we have the last nav item
        if ($this->hasNext()) {
            $output .= '<li><a href="' . $url . '">' . $name . '</a>';
        } else {
            $output .= '<li class="last"><a href="' . $url . '">' . $name . '</a>';
        }

        // either add a subnav or close the list item
        if ($this->hasChildren()) {
            $output .= '<ul>';
        } else {
            $output .= '</li>';
        }

        // cache the depth
        $this->_depth = $this->_curDepth;

        // return the output ( we could've also overridden current())
        return $output;
    }

}
?>

Usage

使用

<?php

try {

    // generate the recursive caching iterator
    $it = new RecursiveCachingIterator(new RecursiveArrayIterator($nav));

    // build the navigation with the iterator
    $it = new NavBuilder($it, RecursiveIteratorIterator::SELF_FIRST);

    // display the resulting navigation
    echo '<ul id="nav">' . PHP_EOL;
    foreach ($it as $value) {
        echo $value . "\n";
    }
    echo '</ul>' . PHP_EOL;

} catch (Exception $e) {
    var_dump($e); die;
}
?>

#2

Do you need a class iterator for this? You could do this with just a simple function...

为此需要一个类迭代器吗?你可以用一个简单的函数来做…

function arrayToListHTML($array, $level = 0) {
    static $tab = "\t";
    if (empty($array)) return;
    $tabs = str_repeat($tab, $level * 2);
    $result = "{$tabs}<ul>\n";
    foreach ($array as $i => $node):
        $result .= "{$tabs}{$tab}<li>\n{$tabs}{$tab}{$tab}{$node['title']}\n".arrayToListHTML($node['children'], $level + 1)."{$tabs}{$tab}</li>\n";
    endforeach;
    $result .= "{$tabs}</ul>\n";
    return $result;
}

Which will produce this output:

产出如下:

<ul>
    <li>
        NodeLvl1
    </li>
    <li>
        NodeLvl1
        <ul>
            <li>
                NodeLvl2
            </li>
            <li>
                NodeLvl2
                <ul>
                    <li>
                        NodeLvl3
                    </li>
                    <li>
                        NodeLvl3
                    </li>
                </ul>
            </li>
        </ul>
    </li>
    <li>
        NodeLvl1
    </li>
</ul>

This covers what you've shown us, but I'm not sure what you mean by other properties. Are there more properties in each array other than title and children?

这包括你给我们看的东西，但我不确定你说的其他属性是什么意思。每个数组中除了标题和子元素之外还有其他属性吗?

#3

Instead of trying to use your class like an array in foreach() consider using your class to perform the function. For instance, the following code will output correctly but the function is performed inside the class.

不要尝试使用类来在foreach()中使用类来执行函数。例如，以下代码将正确地输出，但函数在类中执行。

class It extends RecursiveIteratorIterator{

  protected
    $tab    = "\t";

  public function beginChildren(){

    if(count($this->getInnerIterator()) == 0)
      return;
    echo str_repeat($this->tab, $this->getDepth())."<ul>\n";
  }

  public function endChildren(){


    if(count($this->getInnerIterator()) == 0)
      return;

    echo str_repeat($this->tab, $this->getDepth)."\n</ul>";
  }

  public function nextElement(){
    echo str_repeat($this->tab, $this->getDepth())."<li>".$this->current()."</li>\n";
  }

}

$it = new It(new RecursiveArrayIterator($nodes));
foreach($it as $key => $item)
  //echo $item;
  //it will be better to write a function inside your custom iterator class to handle iterations
?>

#4

First let me explain few things to you. Your array has two pattens

首先让我向你解释一些事情。您的数组有两个pattens。

1. One with numeric indexes
2. 一个数字索引
3. One with string indexes, with title and children which has be parsed differently
4. 一个有字符串索引，有标题和子，但有不同的解析。

I think a recursive function plays very nice role on this part, rather than complex logics. And our recursive function has to be able to handle both patterns separately.

我认为递归函数在这一部分中扮演非常重要的角色，而不是复杂的逻辑。我们的递归函数必须能够分别处理这两个模式。

Here is my version of the function you could use with explanation

function arraytolist(Array $array) { //ensure what you receive is array
  if(count($array)) { //only if it has some items
    //In case the array has `title` index we encountered out PATTERN 2
    if(isset($array['title'])) {
        $o = "<li>";
        $o .= $array['title']; //simply add the title
        $o .= arraytolist($array['children']); //and pass the children to this function to verify again
        $o .= "</li>";
    } else { //if its a normal array, //PATTERN 1
        $o = "<ul>";
        foreach($array as $value) {
            $n = "";
            if(is_array($value)) {  //in case its an array again, 
                //send it to this very same function so that it will return as output again
                $n .= arraytolist($value);
            } else {
                $n .= "<li>$value</li>";
            }
            $o .= strlen($n) ? $n : ""; //if $n has something use it otherwise not
        }
        $o .= "</ul>"; //lets close the ul
    }
    return $o;
  }
}

Some Advantage of this function

• No iteration level
• 没有迭代水平
• As long as its an array and has item, keeps on building them
• 只要它有一个数组和一个项目，就继续构建它们
• Power of simple logic in PHP
• PHP中简单逻辑的强大功能

#5

I would opt for a simple recursive function that flattens the array into the text/html format:

我选择一个简单的递归函数，将数组压缩成文本/html格式:

function arrToList( $arr, $embedded = false ) {
    $output = array();
    if ( $embedded ) $output[] = '<li>';
    $output[] = '<ul>';
    foreach ( $arr as $key => $values ) {
        $output[] = '<li>'.$values['title'].'</li>';
        if ( $values['children'] ) {
            $output[] = arrToList( $values['children'], true );
        }
    }
    $output[] = '</ul>';
    if ( $embedded ) $output[] = '</li>';
    return implode(PHP_EOL, $output);
}

Output from using your input:

使用您的输入输出:

• NodeLvl1
• NodeLvl1
• NodeLvl1
• NodeLvl1
• • NodeLvl2
  • NodeLvl2
  • NodeLvl2
  • NodeLvl2
  • • NodeLvl3
    • NodeLvl3
    • NodeLvl3
    • NodeLvl3
  • NodeLvl3 NodeLvl3
• NodeLvl2 NodeLvl2 NodeLvl3 NodeLvl3
• NodeLvl1
• NodeLvl1

or the actual code:

或实际的代码:

<ul>
<li>NodeLvl1</li>
<li>NodeLvl1</li>
<li>
<ul>
<li>NodeLvl2</li>
<li>NodeLvl2</li>
<li>
<ul>
<li>NodeLvl3</li>
<li>NodeLvl3</li>
</ul>
</li>
</ul>
</li>
<li>NodeLvl1</li>
</ul>

Cheers

干杯