Create nested list from PHP array for dropdown select field

Try this;

function buildTree(Array $data, $parent = 0) {    $tree = array();    foreach ($data as $d) {        if ($d['parent'] == $parent) {            $children = buildTree($data, $d['id']);            // set a trivial key            if (!empty($children)) {                $d['_children'] = $children;            }            $tree[] = $d;        }    }    return $tree;}$rows = array(    array ('id' => 1, 'name' => 'Test 1', 'parent' => 0),    array ('id' => 2, 'name' => 'Test 1.1', 'parent' => 1),    array ('id' => 3, 'name' => 'Test 1.2', 'parent' => 1),    array ('id' => 4, 'name' => 'Test 1.2.1', 'parent' => 3),    array ('id' => 5, 'name' => 'Test 1.2.2', 'parent' => 3),    array ('id' => 6, 'name' => 'Test 1.2.2.1', 'parent' => 5),    array ('id' => 7, 'name' => 'Test 2', 'parent' => 0),    array ('id' => 8, 'name' => 'Test 2.1', 'parent' => 7),);$tree = buildTree($rows);// print_r($tree);function printTree($tree, $r = 0, $p = null) {    foreach ($tree as $i => $t) {        $dash = ($t['parent'] == 0) ? '' : str_repeat('-', $r) .' ';        printf("\t<option value='%d'>%s%s</option>\n", $t['id'], $dash, $t['name']);        if ($t['parent'] == $p) {            // reset $r            $r = 0;        }        if (isset($t['_children'])) {            printTree($t['_children'], ++$r, $t['parent']);        }    }}print("<select>\n");printTree($tree);print("</select>");

Output;

<select>    <option value='1'>Test 1</option>    <option value='2'>- Test 1.1</option>    <option value='3'>- Test 1.2</option>    <option value='4'>-- Test 1.2.1</option>    <option value='5'>-- Test 1.2.2</option>    <option value='6'>--- Test 1.2.2.1</option>    <option value='7'>Test 2</option>    <option value='8'>- Test 2.1</option></select>

And in your case;

<select>    <option value='1'>Baden-Württemberg</option>    <option value='2'>- DMP-Verträge</option>    <option value='50'>- Sprechstundenbedarf</option>    <option value='52'>- Richtgrößen</option>    <option value='53'>- Prüfungen</option>    <option value='54'>- DMP-Verträge</option>    <option value='55'>- Sonstige Verträge</option>    <option value='3'>Berlin</option>    <option value='62'>- DMP-Verträge</option>    <option value='63'>- Prüfungen</option>    <option value='64'>- Richtgrößen</option>    <option value='65'>- Sonstige Verträge</option>    <option value='66'>- Sprechstundenbedarf</option>    <option value='4'>Brandenburg</option>    <option value='67'>- DMP-Verträge</option>    <option value='68'>- Prüfungen</option>    <option value='69'>- Richtgrößen</option>    <option value='70'>- Sonstige Verträge</option>    <option value='71'>- Sprechstundenbedarf</option>    <option value='5'>Bremen</option>    <option value='72'>- DMP-Verträge</option>    <option value='73'>- Prüfungen</option>    <option value='74'>- Richtgrößen</option>    <option value='75'>- Sonstige Verträge</option>    <option value='76'>- Sprechstundenbedarf</option>    <option value='7'>Hessen</option>    <option value='6'>Hamburg</option>    <option value='8'>Mecklenburg-Vorpommern</option>    <option value='9'>Niedersachsen</option>    <option value='10'>Nordrhein</option>    <option value='11'>Rheinland-Pfalz</option>    <option value='12'>Saarland</option>    <option value='13'>Sachsen</option>    <option value='14'>Sachsen-Anhalt</option>    <option value='15'>Schleswig-Holstein</option>    <option value='16'>Thüringen</option>    <option value='17'>Westfalen-Lippe</option>    <option value='51'>Richtgrössen</option>    <option value='56'>Bayern</option>    <option value='57'>- DMP-Verträge</option>    <option value='58'>- Prüfungen</option>    <option value='59'>- Richtgrößen</option>    <option value='60'>- Sonstige Verträge</option>    <option value='61'>- Sprechstundenbedarf</option></select>

this just litle change of the original code that answered by Qeremy

function printTree($tree, $r = 0, $p = null) {    foreach ($tree as $i => $t) {        $dash = ($t['parent'] == 0) ? '' : str_repeat('-', $r) .' ';        printf("\t<option value='%d'>%s%s</option>\n", $t['id'], $dash, $t['name']);        if (isset($t['_children'])) {            printTree($t['_children'], $r+1, $t['parent']);         }    }}

Now the dashed name works great.*sorry for my english

In Qeremy's code just change this line and the code will not be giving you any incrementing dashes

$t['parent'] == $p

to ->

$t['parent'] == 0