复制代码 代码如下:$area = array(array("id"=>1,"name"=>"安徽","parent"=>0),array("id"=>2,"name"=>"海淀","parent"=>7),array("id"=>3,"name"=>"濉溪县","parent"=>5),array("id"=>4,"name"=>"昌平","parent"=>7),array("id"=>5,"name"=>"淮北","parent"=>1),array("id"=>6,"name"=>"朝阳","parent"=>7),array("id"=>7,"name"=>"北京","parent"=>0),array("id"=>8,"name"=>"上地","parent"=>2));
1.递归，查找子孙树
复制代码 代码如下:function subtree($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"]),$v["name"],"<br />";}
2.递归，求家谱树
家谱树的应用 ,如面包屑导航 首页 > 手机类型 > CDMA手机 > 公益PHP > 递归应用
复制代码 代码如下:function familytree($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
复制代码 代码如下:// 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));
