Question

I can’t for the life of me convert my array to a nested UL LI tree, I’ve been attempting it all day but there must be some flaw that I cannot spot (probably because my array isn’t a very simple one).

Basically the array takes the form:

$array = array(
  "0" => array(
    "0" => array("letter" => "A", "data" => "123"), 
    "1" => array(
      "0" => array(
        "0" => array("letter" => "B", "data" => "123"), 
        "1" => array(
          "0" => array(
            "0" => array("letter" => "C", "data" => "123")
          )
        )
      ), 
      "1" => array(
        "0" => array("letter" => "D", "data" => "123"), 
        "1" => array(
          "0" => array(
            "0" => array("letter" => "E", "data" => "123")
          )
        )
      )
    )
  )
);

Explaining Array Above

The arrays come in pairs – the first number being the group, and the second being the row. The above has 3 columns (or levels as I call them) and there is only has one ‘group’.

So [0][0] would be group 0, first row, [0][1][0][0] would be the second row of level one, but is the first row of level 2, and so one.

Where basically I want the result to appear as follows (for the example above):

<ul id="mylist">
    <li>
        <ul class="initial">
            <li>A</li>
            <li class="top">
                <ul class="wrap">
                    <li>
                        <ul class="inner">
                            <li>B</li>
                            <li class="top">
                                <ul class="wrap">
                                    <li>
                                        <ul class="inner">
                                            <li>C</li>
                                        </ul>
                                    </li>
                                    <li class="end"><a class="add">Add</a></li>
                                </ul>
                            </li>
                        </ul>
                    </li>
                    <li>
                        <ul class="inner">
                            <li>D</li>
                            <li class="top">
                                <ul class="wrap">
                                    <li>
                                        <ul class="inner">
                                            <li>E</li>
                                        </ul>
                                    </li>
                                    <li class="end"><a class="add">Add</a></li>
                                </ul>
                            </li>
                        </ul>
                    </li>
                    <li class="end"><a class="add">Add</a></li>
                </ul>
            </li>
        </ul>
    </li>
    <li class="end"><a class="add">Add</a></li>
</ul>

Basically, an ‘add’ appears at the end of each node branch (last list item within ‘wrap’ class).

I’ve done the following so far, but I feel it isn’t correct at all, and doesn’t work correctly if additional nodes were added or nodes were removed.

function recursion($data, $level){

    $skip = array_key_exists('data', $data[0]) ? 0 : 1;

    if($skip == 0){
        $level++;
        if($level !== 1){
            $out .= "<li>\n";
        }
        if($level == 1){
            $out .= "<ul class='initial'>\n";
        } else {
            $out .= "<ul class='inner'>\n";
        }
    }
    $count = 0;
    $loop_count = 0;
    $show_end = 0;
    foreach($data as $key => $value){
        $loop_count++;
        if(is_array($value) && array_key_exists('data', $value)){
            $count++;

            $out .= ($skip == 0) ? "<li>" : "";

            if($value['data'] == "123"){
                $out .= $value['letter'];
            }

            if(!is_array($data[($key+1)][0])){
                $out .= "</li>\n";
                $out .= "<li class=\"end\"><a class=\"add\">Add</a></li>\n";

                $out .= "</ul>\n";
                $out .= "</li>\n";
                $out .= "</ul>\n";
                $out .= "</li>\n";

                $out .= "<li class=\"end\"><a class=\"add\">Add</a></li>\n";

                $show_end = 1;
            }
            $last_key = $key;
        } else if(is_array($value)){
            $out.= recursion($value, $level);
        }
        if($show_end == 1){
            $out .= "</ul>\n";
        }
        if(is_array($value) && array_key_exists('data', $value) && !is_array($data[($key+1)])){
            $out .= "</li>\n";
        }
        if($show_end == 1 && count($data) !== $count){
            $out .= "<li>\n";
        }
    }

    return $out;
}

Output of

 print_r($array, true) 

Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [letter] => A
                    [data] => 123
                )

            [1] => Array
                (
                    [0] => Array
                        (
                            [0] => Array
                                (
                                    [0] => Array
                                        (
                                            [letter] => B
                                            [data] => 123
                                        )

                                    [1] => Array
                                        (
                                            [0] => Array
                                                (
                                                    [0] => Array
                                                        (
                                                            [letter] => C
                                                            [data] => 123
                                                        )

                                                )

                                        )

                                )

                            [1] => Array
                                (
                                    [0] => Array
                                        (
                                            [letter] => D
                                            [data] => 123
                                        )

                                    [1] => Array
                                        (
                                            [0] => Array
                                                (
                                                    [0] => Array
                                                        (
                                                            [letter] => E
                                                            [data] => 123
                                                        )

                                                )

                                        )

                                )

                        )

                )

        )

)

Answer 1

Are you sure your array structure matches the HTML you have shown? I tweaked the array and came up with this function that seems to work.

function build_list($array, $level=0)
{
    foreach($array as $group)
    {
        echo '<li>';
        if(isset($group['letter']))
        {
            echo $group['letter'];
        }
        else            
        {
            $class = 'wrap';
            if($level%2 == 1)
            {
                $class = 'inner';
            }
            echo '<ul class="' . $class . '">';
            build_list($group, $level+1);
            if($class == 'wrap')
            {
                echo '<li class="end"><a class="add">Add</a></li>';
            }
            echo '</ul>';
        }
        echo '</li>';
    }
}

Here are my changes to the array:

$array = 
array
(
    array("letter" => "A", "data" => "123"), //li
    array //li ul
    (
        array //li ul
        (
            array("letter" => "B", "data" => "123"), //li
            array //li ul
            (
                array //li ul
                (
                    array("letter" => "C", "data" => "123")
                )
            )
        ),
        array
        (
            array("letter" => "D", "data" => "123"), 
            array
            (
                array
                (
                    array("letter" => "E", "data" => "123")
                )
            )
        )
    )
);

Then to call it:

<ul class="inital">
<?php
build_list($array);
?>
</ul>