PHP RecursiveIteratorIterator:确定每个分支级别的第一项和最后一项 [英] PHP RecursiveIteratorIterator: Determining first and last item at each branch level

问题描述

我扩展了Zend_View_Helper_Navigation_Menu，它使用RecursiveIteratorIterator遍历菜单树.我想确定的是我是在树中分支级别的第一项还是最后一项.

I have extended Zend_View_Helper_Navigation_Menu, and it uses a RecursiveIteratorIterator to iterate over the menu tree. What I want to be able to determine is whether I am on the first or last item for a branch level in the tree.

以下是我正在寻找的示例:

Here's an example of what I'm looking for:

• 导航1(第一个)
  • 导航1.1(第一个和最后一个)
    • 导航1.1.1(第一个)
    • 导航1.1.2
    • 导航1.1.3(最后)
    • Nav 1 (first)
      • Nav 1.1 (first & last)
        • Nav 1.1.1 (first)
        • Nav 1.1.2
        • Nav 1.1.3 (last)
        • 导航2.1(第一个)
        • 导航2.2(最新)
        • 导航3.1(第一个)
        • 导航3.2(最后)

        其他信息

        • PHP版本5.2.13

        解决方案

        在foreach ($iterator as $page)循环中，两个变量可用于跟踪深度$depth和$prevDepth.然后，一个简单的比较条件就可以确定分支级别中的第一项:if ($depth > $prevDepth).

        Within the foreach ($iterator as $page) loop two variables can be used to keep track of the depths, $depth and $prevDepth. A simple comparison conditional can then determine the first item in a branch level: if ($depth > $prevDepth).

        使用Zend_Navigation_Container对象创建RecursiveCachingIterator，然后使用该对象创建RecursiveIteratorIterator会添加hasNext()方法.

        Creating a RecursiveCachingIterator using the Zend_Navigation_Container object and then using that to create the RecursiveIteratorIterator adds the the hasNext() method.

        $rci = new RecursiveCachingIterator($container, CachingIterator::FULL_CACHE);
        $iterator = new RecursiveIteratorIterator($rci,
                            RecursiveIteratorIterator::SELF_FIRST);
        /* snip */
        $prevDepth = -1;
        foreach ($iterator as $page) {
            $depth = $iterator->getDepth();
            /* snip */
            if ($depth > $prevDepth) {
                // first branch item
            }
            /* snip */
            if (!$iterator->hasNext()) {
                // last branch item
            }
            /* snip */
            $prevDepth = $depth;
        }
        

        推荐答案

        使用RecursiveCachingIterator:

        Using RecursiveCachingIterator:

        $rdi = new RecursiveDirectoryIterator('.');
        $rci = new RecursiveCachingIterator($rdi, CachingIterator::FULL_CACHE); 
        $rii = new RecursiveIteratorIterator($rci, RecursiveIteratorIterator::SELF_FIRST);
        
        foreach ($rii as $file) {
            if ($file->isDir()) {
                echo $file->getFilename() . PHP_EOL;
            }
            elseif (!$rii->hasNext()) {
                echo $file->getFilename() . PHP_EOL;
            }
            elseif (count($rii->getCache()) == 1) {
                echo $file->getFilename() . PHP_EOL;
            }
        }
        

        具有数组的另一种解决方案:

        Another solution with array:

        function buildTree(RecursiveDirectoryIterator $iterator) {
            $tree = array();
            foreach ($iterator as $fileinfo) {
                if ($fileinfo->isDir()) {
                    $tree[$fileinfo->getFilename()] = buildTree($iterator->getChildren());
                } else {
                    $tree[$fileinfo->getFilename()] = $fileinfo->getFilename();
                }
            }
            return $tree;
        }
        
        function filterTree(array $tree) {
            foreach ($tree as $key => $value) {
                if (is_array($value)) {
                    $tree[$key] = filterTree($value);
                } elseif (reset($tree) !== $value && end($tree) !== $value) {
                    unset($tree[$key]);
                }
            }
            return $tree;
        }
        
        print_r(filterTree(buildTree(new RecursiveDirectoryIterator('.'))));
        

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