PHP实现无限极分类生成分类树的方法

本文实例讲述了PHP实现无限极分类生成分类树的方法。分享给大家供大家参考，具体如下： 现在的分类数据库设计基本都是：每一个分类有一个id主键字段，一个pid指向父类的id，这样便可实现无限级分类，取出的数据就是如下的格式：

$arr = array(
array("id" => 1 , "pid" => 0 , 'cat' => '栏目一'),
array("id" => 2 , "pid" => 0 , 'cat' => '栏目二'),
array("id" => 3 , "pid" => 1 , 'cat' => '栏目三'),
array("id" => 4 , "pid" => 2 , 'cat' => '栏目四'),
array("id" => 5 , "pid" => 1 , 'cat' => '栏目五'),
array("id" => 6 , "pid" => 5 , 'cat' => '栏目六'),
array("id" => 7 , "pid" => 5 , 'cat' => '栏目七'),
array("id" => 8 , "pid" => 6 , 'cat' => '栏目八'),
array("id" => 9 , "pid" => 1 , 'cat' => '栏目九'),
array("id" => 10 , "pid" => 0 , 'cat' => '栏目十'),
array("id" => 11 , "pid" => 10 , 'cat' => '栏目十一'),
array("id" => 12 , "pid" => 11 , 'cat' => '栏目十二'),
array("id" => 13 , "pid" => 2 , 'cat' => '栏目十三'),
array("id" => 14, "pid" => 13 , 'cat' => '栏目十四')
);

不多说，直接上处理代码：

//生成无限极分类树
function make_tree($arr){
$refer = array();
$tree = array();
foreach($arr as $k => $v){
$refer[$v['id']] = & $arr[$k]; //创建主键的数组引用
}
foreach($arr as $k => $v){
$pid = $v['pid']; //获取当前分类的父级id
if($pid == 0){
$tree[] = & $arr[$k]; //顶级栏目
}else{
if(isset($refer[$pid])){
$refer[$pid]['subcat'][] = & $arr[$k]; //如果存在父级栏目，则添加进父级栏目的子栏目数组中
}
}
}
return $tree;
}

测试运行：

$cat = make_tree($arr); print_r($cat);

运行结果：

Array ( [0] => Array ( [id] => 1 [pid] => 0 [cat] => 栏目一 [subcat] => Array ( [0] => Array ( [id] => 3 [pid] => 1 [cat] => 栏目三 ) [1] => Array ( [id] => 5 [pid] => 1 [cat] => 栏目五 [subcat] => Array ( [0] => Array ( [id] => 6 [pid] => 5 [cat] => 栏目六 [subcat] => Array ( [0] => Array ( [id] => 8 [pid] => 6 [cat] => 栏目八 ) ) ) [1] => Array ( [id] => 7 [pid] => 5 [cat] => 栏目七 ) ) ) [2] => Array ( [id] => 9 [pid] => 1 [cat] => 栏目九 ) ) ) [1] => Array ( [id] => 2 [pid] => 0 [cat] => 栏目二 [subcat] => Array ( [0] => Array ( [id] => 4 [pid] => 2 [cat] => 栏目四 ) [1] => Array ( [id] => 13 [pid] => 2 [cat] => 栏目十三 [subcat] => Array ( [0] => Array ( [id] => 14 [pid] =>/【本文中一些MYSQL版本可能是以前的，MYSQL建议使用5.7以上的版本】/; 13 [cat] => 栏目十四 ) ) ) ) ) [2] => Array ( [id] => 10 [pid] => 0 [cat] => 栏目十 [subcat] => Array ( [0] => Array ( [id] => 11 [p//id] => 10 [cat] => 栏目十一 [subcat] => Array ( [0] => Array ( [id] => 12 [pid] => 11 [cat] => 栏目十二 ) ) ) ) ) )

如果大家需要这样的组装格式，或者需要该格式方便后续的处理，可以尝试此方法

希望本文所述对大家PHP程序设计有所帮助。