Combine output of recursive function in one variable

Question

i am using recursive function to echo multi-level navigation scheme in code-igniter it echo's fine but i want to combine that output in one varible and want to return it from where the function is called please, help me here is my code

    function parseAndPrintTree($root, $tree)
    {
        if(!is_null($tree) && count($tree) > 0) 
                {
                echo 'ul';
                foreach($tree as $child => $parent) 
                    {
                    if($parent->parent == $root) 
                        {

                        unset($tree[$child]);
                        echo 'li';
                        echo $parent->name;
                        parseAndPrintTree($parent->entity_id, $tree);
                        echo 'li close';
                        }
                    }
                echo 'ul close';
        }
    }
    

Answer 1

You just build up a string using the . concatenator symbol (NB no space between the . and = now!)

function parseAndPrintTree($root, $tree)
{
    if(!is_null($tree) && count($tree) > 0) 
            {
            $data = 'ul';
            foreach($tree as $child => $parent) 
                {
                if($parent->parent == $root) 
                    {

                    unset($tree[$child]);
                    $data .= 'li';
                    $data .= $parent->name;
                    parseAndPrintTree($parent->entity_id, $tree);
                    $data .= 'li close';
                    }
                }
            $data .= 'ul close';
    }
return $data;
}

// then where you want your ul to appear ...
echo parseAndPrintTree($a, $b);

A better name might be treeToUl() or something similar, stating better what your intention is for this code ( a html unordered list?)

You can also keep your html output readable by adding some line ends like this:

$data .= '</ul>' . PHP_EOL;

Answer 2

Try this one:

function parseAndPrintTree($root, $tree)
{
    $output = '';

    if(!is_null($tree) && count($tree) > 0) 
        {
                $output .= 'ul';
                foreach($tree as $child => $parent) 
                    {
                    if($parent->parent == $root) 
                        {

                        unset($tree[$child]);
                        $output .=  'li';
                        $output .= $parent->name;
                        $output .= parseAndPrintTree($parent->entity_id, $tree);
                        $output .= 'li close';
                        }
                    }
                $output.= 'ul close';
    }

    return $output;
}