PHP实现无限级分类（不使用递归）

PHP实战
<?php
 $list = array(
 array('id'=>1,'fid'=>0,'title' => '中国'),array('id'=>2,'fid'=>1,'title' => '江苏'),array('id'=>3,'title' => '安徽'),array('id'=>4,'fid'=>8,'title' => '江阴'),array('id'=>5,'fid'=>3,'title' => '芜湖'),array('id'=>6,'title' => '合肥'),array('id'=>7,'title' => '蚌埠'),array('id'=>8,'title' => '无锡')
 );
?>

PHP实战
<ul>
 <li class="first-child">
 <div>江苏</div>
 <ul>
 <li class="first-child last-child">
 <div>无锡</div>
 <ul>
 <li class="first-child last-child">
 <div>江阴</div>
 </li>
 </ul>
 </li>
 </ul>
 </li>
 <li class="last-child">
 <div>安徽</div>
 <ul>
 <li class="first-child"><div>芜湖</div></li>
 <li><div>合肥</div></li>
 <li class="last-child"><div>蚌埠</div></li>
 </ul>
 </li>
</ul>

PHP实战
<ul><?php echo get_tree_ul($list,1); ?></ul>

PHP实战
<select>
 <option value="2">江苏</option>
 <option value="8">????无锡</option>
 <option value="4">????????江阴</option>
 <option value="3">安徽</option>
 <option value="5">????芜湖</option>
 <option value="6">????合肥</option>
 <option value="7">????蚌埠</option>
</select>

PHP实战
<select>
<?php
 // get_tree_option()返回数组,并为每个元素增加了“深度”(即depth)列,直接输出即可
 $options = get_tree_option($list,1); 
 foreach($options as $op) {
 echo '<option value="' . $op['id'] .'">' . str_repeat(" ",$op['depth'] * 4) . $op['title'] . '<;/option>';
 }
?>
<;/select>

PHP实战
<?php
 $children = get_tree_child($list,0);
 echo implode(',',$children); // 输出：1,3,2,7,6,5,8,4
?>

PHP实战
<?php
 $children = get_tree_parent($list,4);
 echo implode(',$children); //8,10
?>

PHP实战
<?php
function get_tree_child($data,$fid) {
 $result = array();
 $fids = array($fid);
 do {
 $cids = array();
 $flag = false;
 foreach($fids as $fid) {
 for($i = count($data) - 1; $i >=0 ; $i--) {
 $node = $data[$i];
 if($node['fid'] == $fid) {
 array_splice($data,$i,1);
 $result[] = $node['id'];
 $cids[] = $node['id'];
 $flag = true;
 }
 }
 }
 $fids = $cids;
 } while($flag === true);
 return $result;
}
function get_tree_parent($data,$id) {
 $result = array();
 $obj = array();
 foreach($data as $node) {
 $obj[$node['id']] = $node;
 } 
 $value = isset($obj[$id]) ? $obj[$id] : null; 
 while($value) {
 $id = null;
 foreach($data as $node) {
 if($node['id'] == $value['fid']) {
 $id = $node['id'];
 $result[] = $node['id'];
 break;
 }
 }
 if($id === null) {
 $result[] = $value['fid'];
 }
 $value = isset($obj[$id]) ? $obj[$id] : null;
 }
 unset($obj);
 return $result;
}
function get_tree_ul($data,$fid) {
 $stack = array($fid);
 $child = array();
 $added_left = array();
 $added_right= array();
 $html_left = array();
 $html_right = array();
 $obj = array();
 $loop = 0;
 foreach($data as $node) {
 $pid = $node['fid'];
 if(!isset($child[$pid])) {
 $child[$pid] = array();
 }
 array_push($child[$pid],$node['id']);
 $obj[$node['id']] = $node;
 }
 while (count($stack) > 0) { 
 $id = $stack[0];
 $flag = false;
 $node = isset($obj[$id]) ? $obj[$id] : null;
 if (isset($child[$id])) {
 $cids = $child[$id];
 $length = count($cids);
 for($i = $length - 1; $i >= 0; $i--) {
 array_unshift($stack,$cids[$i]);
 }
 $obj[$cids[$length - 1]]['isLastChild'] = true;
 $obj[$cids[0]]['isFirstChild'] = true;
 $flag = true;
 }
 if ($id != $fid && $node && !isset($added_left[$id])) {
 if(isset($node['isFirstChild']) && isset($node['isLastChild'])) {
 $html_left[] = '<li class="first-child last-child">';
 } else if(isset($node['isFirstChild'])) {
 $html_left[] = '<li class="first-child">';
 } else if(isset($node['isLastChild'])) {
 $html_left[] = '<li class="last-child">';
 } else {
 $html_left[] = '<li>';
 } 
 $html_left[] = ($flag === true) ? "<div>{$node['title']}</div><ul>" : "<div>{$node['title']}</div>";
 $added_left[$id] = true;
 } 
 if ($id != $fid && $node && !isset($added_right[$id])) {
 $html_right[] = ($flag === true) ? '</ul></li>' : '</li>';
 $added_right[$id] = true;
 }
 if ($flag == false) {
 if($node) {
 $cids = $child[$node['fid']];
 for ($i = count($cids) - 1; $i >= 0; $i--) {
 if ($cids[$i] == $id) {
 array_splice($child[$node['fid']],1);
 break;
 }
 } 
 if(count($child[$node['fid']]) == 0) {
 $child[$node['fid']] = null;
 }
 }
 array_push($html_left,array_pop($html_right));
 array_shift($stack);
 }
 $loop++;
 if($loop > 5000) return $html_left;
 }
 unset($child);
 unset($obj);
 return implode('',$html_left);
}
function get_tree_option($data,$fid) {
 $stack = array($fid);
 $child = array();
 $added = array();
 $options = array();
 $obj = array();
 $loop = 0;
 $depth = -1;
 foreach($data as $node) {
 $pid = $node['fid'];
 if(!isset($child[$pid])) {
 $child[$pid] = array();
 }
 array_push($child[$pid],$node['id']);
 $obj[$node['id']] = $node;
 }
 while (count($stack) > 0) { 
 $id = $stack[0];
 $flag = false;
 $node = isset($obj[$id]) ? $obj[$id] : null;
 if (isset($child[$id])) {
 for($i = count($child[$id]) - 1; $i >= 0; $i--) {
 array_unshift($stack,$child[$id][$i]);
 }
 $flag = true;
 }
 if ($id != $fid && $node && !isset($added[$id])) {
 $node['depth'] = $depth;
 $options[] = $node;
 $added[$id] = true;
 }
 if($flag == true){
 $depth++;
 } else {
 if($node) {
 for ($i = count($child[$node['fid']]) - 1; $i >= 0; $i--) {
 if ($child[$node['fid']][$i] == $id) {
 array_splice($child[$node['fid']],1);
 break;
 }
 } 
 if(count($child[$node['fid']]) == 0) {
 $child[$node['fid']] = null;
 $depth--;
 }
 }
 array_shift($stack);
 }
 $loop++;
 if($loop > 5000) return $options;
 }
 unset($child);
 unset($obj);
 return $options;
}
?>