$area = array(
array('id'=>1,'name'=>'安徽','parent'=>0),
array('id'=>2,'name'=>'海淀','parent'=>7),
array('id'=>3,'name'=>'濉溪县','parent'=>5),
array('id'=>4,'name'=>'昌平','parent'=>7),
array('id'=>5,'name'=>'淮北','parent'=>1),
array('id'=>6,'name'=>'朝阳','parent'=>7),
array('id'=>7,'name'=>'北京','parent'=>0),
array('id'=>8,'name'=>'上地','parent'=>2)
function subtree($arr,$id=0,$lev=1) {
$subs = array(); // 子孙数组
foreach($arr as $v) {
if($v['parent'] == $id) {
$v['lev'] = $lev;
$subs[] = $v; // 举例说找到array('id'=>1,'name'=>'安徽','parent'=>0),
$subs = array_merge($subs,subtree($arr,$v['id'],$lev+1));
}
}
return $subs;
}
$tree = subtree($area,0,1);
foreach($tree as $v) {
echo str_repeat(' ',$v['lev']),$v['name'],'<br />';
}
2.递归，求家谱树
家谱树的应用 ,如面包屑导航 首页 > 手机类型 > CDMA手机 > 公益PHP > 递归应用
function familytree($arr,$id) {
$tree = array();
foreach($arr as $v) {
if($v['id'] == $id) {// 判断要不要找父栏目
if($v['parent'] > 0) { // parnet>0,说明有父栏目
$tree = array_merge($tree,familytree($arr,$v['parent']));
}
$tree[] = $v; // 以找到上地为例
}
}
return $tree;
}
print_r(familytree($area,8)); // 北京->海淀->上地
// 迭代,效率比递归高,代码也没多.
// 找家谱树推荐用迭代
function tree($arr,$id) {
$tree = array();
while($id !== 0) {
foreach($arr as $v) {
if($v['id'] == $id) {
$tree[] = $v;
$id = $v['parent'];
break;
}
}
}
return $tree;
}
print_r(tree($area,8));