1。分类（分类只有2级的时候会写的更好）$data=[["id"=>1,"name"=>"shanghai","pid"=>0],["id"=>2,"name"=>"北京","pid"=>0],["id"=>3,"name"=>"江苏","pid"=>0],["id"=>4,"name"=>"huangpu","pid"=>1],["id"=>5,"name"=>"dongchengqu","pid"=>2],["id"=>6,"name"=>"苏州","pid"=>3],];$结果=[]；foreach($dataas$value){$pid=$value['pid'];如果（$pid>0）{$result[$pid]['children']=$value;}else{$value['children']=[];$result[$value['id']]=$value;}}
