$area = array( array(‘id‘=>1,‘name‘=>‘安徽‘,‘parent‘=>0), array(‘id‘=>2,‘name‘=>‘海淀‘,‘parent‘=>7), array(‘id‘=>3,‘name‘=>‘濉溪县‘,‘parent‘=>5), array(‘id‘=>4,‘name‘=>‘昌平‘,‘parent‘=>7), array(‘id‘=>5,‘name‘=>‘淮北‘,‘parent‘=>1), array(‘id‘=>6,‘name‘=>‘朝阳‘,‘parent‘=>7), array(‘id‘=>7,‘name‘=>‘北京‘,‘parent‘=>0), array(‘id‘=>8,‘name‘=>‘上地‘,‘parent‘=>2) );
1.递归,查找子孙树
function subtree($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
2.迭代,求家谱树
// 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));
原文:http://www.cnblogs.com/sbfnxk201/p/3807308.html