$arr = [
'id' => 1,
'name' => 'item1',
'items' => [
['id' => 2,
'name' => 'item2',
'items' => [],
],
['id' => 3,
'name' => 'item3',
'items' => [],
],
[
'id' => 4,
'name' => 'item4',
'items' => [
['id' => 5,
'name' => 'item5',
'items' => [],
],
['id' => 6,
'name' => 'item6',
'items' => [],
]
]
]
]
];
function list_form(array $array) {
$str = '';
foreach ($array as $key => $val) {
if (is_array($val)) {
$str .= "<li>$key =></li>";
if (!empty($val)) {
$str .= list_form($val);
}
}
else {
$str .= "<li>$key => $val</li>";
}
}
return "<ul>" . str_replace(["<ul>", "</ul>"], '', $str) . "</ul>";
}
echo list_form($arr);
<?php
function formatList(array $list): string
{
$result = '';
foreach ($list as $key => $value) {
if (!is_array($value)) {
$result .= "<li>{$key} => {$value}</li>";
continue;
}
$result .= "<li>{$key} =></li>";
foreach ($value as $item) {
$result .= formatList($item);
}
}
if ((debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]['function'] ?? '') !== 'formatList') {
$result = "<ul>{$result}</ul>";
}
return $result;
}
print formatList($arr);
<ul><li>id => 1</li><li>name => item1</li><li>items =></li><li>id => 2</li><li>name => item2</li><li>items =></li><li>id => 3</li><li>name => item3</li><li>items =></li><li>id => 4</li><li>name => item4</li><li>items =></li><li>id => 5</li><li>name => item5</li><li>items =></li><li>id => 6</li><li>name => item6</li><li>items =></li></ul>
<?php
$arr = [ 'id' => 1, 'name' => 'item1', 'items' => [
[ 'id' => 2, 'name' => 'item2', 'items' => [], ],
[ 'id' => 3, 'name' => 'item3', 'items' => [], ],
[ 'id' => 4, 'name' => 'item4', 'items' => [
[ 'id' => 5, 'name' => 'item5', 'items' => [], ],
[ 'id' => 6, 'name' => 'item6', 'items' => [], ],
], ],
], ];
function list_form_iterative(array $input) {
$result = [ '<ul>', ];
$state = [ [ 'array' => $input, 'keys' => array_keys($input), 'idx' => 0, ] ];
for (; count($state) > 1 || $state[0]['idx'] < count($state[0]['keys']); $state[0]['idx'] += 1) {
if (count($state) > 1 && $state[0]['idx'] === count($state[0]['keys'])) {
array_shift($state);
continue;
}
$key = $state[0]['keys'][$state[0]['idx']];
$value = $state[0]['array'][$key];
if (!is_array($value)) {
$result[] = "<li>$key => $value</li>";
}
else {
$result[] = "<li>$key => []</li>";
if (!count($value)) continue;
array_unshift($state, [ 'array' => $value, 'keys' => array_keys($value), 'idx' => -1, ]);
}
}
$result[] = '</ul>';
return implode("\n", $result);
}
echo list_form_iterative($arr);
<?php
$arr = [ 'id' => 1, 'name' => 'item1', 'items' => [
[ 'id' => 2, 'name' => 'item2', 'items' => [], ],
[ 'id' => 3, 'name' => 'item3', 'items' => [], ],
[ 'id' => 4, 'name' => 'item4', 'items' => [
[ 'id' => 5, 'name' => 'item5', 'items' => [], ],
[ 'id' => 6, 'name' => 'item6', 'items' => [], ],
], ],
], ];
function list_form_recursive(array $input) {
static $level = 0;
$self = __FUNCTION__;
$result = [];
if (!$level) {
$result[] = '<ul>';
}
foreach ($input as $key => $value) {
if (!is_array($value)) {
$result[] = "<li>$key => $value</li>";
}
else {
$result[] = "<li>$key => []</li>";
if (!count($value)) continue;
$level += 1;
array_push($result, ...$self($value));
$level -= 1;
}
}
if (!$level) {
$result[] = '</ul>';
return implode("\n", $result);
}
else {
return $result;
}
}
echo list_form_recursive($arr);
<ul>
<li>id => 1</li>
<li>name => item1</li>
<li>items => []</li>
<li>0 => []</li>
<li>id => 2</li>
<li>name => item2</li>
<li>items => []</li>
<li>1 => []</li>
<li>id => 3</li>
<li>name => item3</li>
<li>items => []</li>
<li>2 => []</li>
<li>id => 4</li>
<li>name => item4</li>
<li>items => []</li>
<li>0 => []</li>
<li>id => 5</li>
<li>name => item5</li>
<li>items => []</li>
<li>1 => []</li>
<li>id => 6</li>
<li>name => item6</li>
<li>items => []</li>
</ul>
<?php
function list_form(array $items):string
{
function inner(array $items):string {
$result = '';
foreach ($items as $key => $val) {
if (is_array($val) ) {
$result .= "<li>$key =></li>";
if (!empty($val)) {
$result .= inner($val);
}
} else {
$result .= "<li>$key => $val</li>";
}
}
return $result;
}
return '<ul>'.inner($items).'</ul>';
}
echo list_form($arr);