PHP recursively converts categories into arrays

function getTree($data, $pid){

$tree = '';

foreach($data as $k=>$v)
{
if($v['parentid']==$pid )
{

//print_r($this->getTree($data, $v['linkageid']));
$v['parentid'] = $this->getTree($data, $v ['linkageid']);
$tree[] = $v;
}
}
return $tree;
}

The above introduces how PHP recursively converts categories into arrays, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.