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POCreating a single SELECT using multilevel parent->child array
 

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    <p>I used the following stackoverflow <a href="https://stackoverflow.com/questions/2273449/creating-a-multilevel-array-using-parentids-in-php">thread</a>, which was very helpful, in creating a sorted multilevel parent->child array.</p> <p>The below is a sample multi-level (3 levels) parent->child sorted array based on the sorting method of the above stated thread:</p> <pre><code>Array ( [1] =&gt; Array ( [name] =&gt; User Manual [parentId] =&gt; 0 [children] =&gt; Array ( [2] =&gt; Array ( [name] =&gt; Users [parentId] =&gt; 1 [children] =&gt; Array ( [4] =&gt; Array ( [name] =&gt; Privileges [parentId] =&gt; 2 ) ) ) [3] =&gt; Array ( [name] =&gt; Reference [parentId] =&gt; 1 [children] =&gt; Array ( [5] =&gt; Array ( [name] =&gt; Glossary [parentId] =&gt; 3 ) [6] =&gt; Array ( [name] =&gt; Index [parentId] =&gt; 3 ) ) ) ) ) ) </code></pre> <p>Now I'd like to take that sorted array and generate a <strong>single</strong> HTML SELECT that displays and represents the parent->child structure like the below example:</p> <pre><code>&lt;option value='1'&gt;User Manual&lt;/option&gt; &lt;option value='2'&gt;User Manual -&gt; Users&lt;/option&gt; &lt;option value='4'&gt;User Manual -&gt; Users -&gt; Privileges&lt;/option&gt; &lt;option value='3'&gt;User Manual -&gt; Reference&lt;/option&gt; &lt;option value='5'&gt;User Manual -&gt; Reference -&gt; Glossary&lt;/option&gt; &lt;option value='6'&gt;User Manual -&gt; Reference -&gt; Index&lt;/option&gt; </code></pre> <p>The goal as seen above is to compile a display string that represents the multi-level parent/child path for each item. The VALUE to each option is the last item in the represented compiled string. So for the OPTION 'User Manual -> Users -> Privileges' the VALUE is the ID for Privileges, but the display text represents it's parent/child relationship in the array.</p> <p>The select I create always ends up displaying the list of options like the below:</p> <pre><code>&lt;option value='1'&gt;User Manual&lt;/option&gt; &lt;option value='2'&gt;User Manual -&gt; Users&lt;/option&gt; &lt;option value='4'&gt;Users -&gt; Privileges&lt;/option&gt; &lt;option value='3'&gt;User Manual -&gt; Reference&lt;/option&gt; &lt;option value='5'&gt;Reference -&gt; Glossary&lt;/option&gt; &lt;option value='6'&gt;Reference -&gt; Index&lt;/option&gt; </code></pre> <p>You can see that it only is able to keep track of one level of the parent/child relationship.</p> <p>My function that processes the array to create the selects options list is as follows:</p> <pre><code>function buildOptions($arr, $target, $parent = NULL) { $html = ""; foreach ( $arr as $key =&gt; $v ) { if (array_key_exists('children', $v)) { if ( $key == $target ) $html .= "&lt;option value='$key' selected&gt;$parent {$v['name']}&lt;/option&gt;\n"; else $html .= "&lt;option value='$key'&gt;$parent {$v['name']}&lt;/option&gt;\n"; $html .= buildOptions($v['children'],$target,$v['name']." &gt; "); } else if ( $key == $target ) $html .= "&lt;option value='$key' selected&gt;$parent {$v['name']}&lt;/option&gt;\n"; else $html .= "&lt;option value='$key'&gt;$parent {$v['name']}&lt;/option&gt;\n"; } return $html; } </code></pre> <p>I'm having trouble in keeping track of the previous X parent.name when there is more than one level. Any help here would be welcomed. Thank you!</p>
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    1. COWhat does your array look like? Smells like recursion may be involved.
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    2. COYour right, I use recursion to get the 2 levels displayed so the problem I have is retaining the tree structure history past two levels. The problem is the recursion works through a pre-sorted array. It deals with each child and it's children as it progresses, naturally. So when it steps back to a prior child I'm having a hard time conceptualizing stepping back the string. Hopefully that makes sense. I'll update my post with an array example.
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    3. CO@Brad: There is no recursive call in your snippet. What's `toUL`? What's `$target`? Would you consider using visual cues (indentation) instead of repeating the complete path for expressing hierarchy?
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