PHP implements an infinitus classification method to generate a classification tree.

PHP implements an infinitus classification method to generate a classification tree.

This example describes how to generate a classification tree using infinitus classification in PHP. We will share this with you for your reference. The details are as follows:

The current classification database design is basically: Each category has an id primary key field, and a pid points to the id of the parent class, so that you can implement an unlimited classification, the retrieved data is in the following format:

$ Arr = array ("id" => 1, "pid" => 0, 'cat' => 'column 1 '), array ("id" => 2, "pid" => 0, 'cat' => 'column 2'), array ("id" => 3, "pid" => 1, 'cat' => 'column 3'), array ("id" => 4, "pid" => 2, 'cat' => 'column 4'), array ("id" => 5, "pid" => 1, 'cat' => 'column 5 '), array ("id" => 6, "pid" => 5, 'cat' => 'column 6'), array ("id" => 7, "pid" => 5, 'cat' => 'column 7'), array ("id" => 8, "pid" => 6, 'cat' => 'column 8'), array ("id" => 9, "pid" => 1, 'cat' => 'column 9 '), array ("id" => 10, "pid" => 0, 'cat' => 'column 10'), array ("id" => 11, "pid" => 10, 'cat' => 'column 11'), array ("id" => 12, "pid" => 11, 'cat' => 'column 12'), array ("id" => 13, "pid" => 2, 'cat' => 'column 13 '), array ("id" => 14, "pid" => 13, 'cat' => 'column 14 '));

Not to mention, process the Code directly:

// Function make_tree ($ arr) {$ refer = array (); $ tree = array (); foreach ($ arr as $ k => $ v) {$ refer [$ v ['id'] = & $ arr [$ k]; // create an array reference for the primary key} foreach ($ arr as $ k => $ v) {$ pid = $ v ['pid']; // obtain the parent id of the current category if ($ pid = 0) {$ tree [] = & $ arr [$ k]; // top-level topic} else {if (isset ($ refer [$ pid]) {$ refer [$ pid] ['subcat'] [] = & $ arr [$ k]; // if a parent Column exists, add it to the parent column's subcolumn array }}return $ tree ;}

Test run:

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

Running result:

Array ([0] => Array ([id] => 1 [pid] => 0 [cat] => Topic 1 [subcat] => Array ([0] => array ([id] => 3 [pid] => 1 [cat] => column 3) [1] => Array ([id] => 5 [pid] => 1 [cat] => Topic 5 [subcat] => Array ([0] => Array ([id] => 6 [pid] => 5 [cat] => column 6 [subcat] => Array ([0] => Array ([id] => 8 [pid] => 6 [cat] => Column 8 ))) [1] => Array ([id] => 7 [pid] => 5 [cat] => column 7 ))) [2] => Array ([id] => 9 [pid] => 1 [cat] => Topic 9 ))) [1] => Array ([id] => 2 [pid] => 0 [cat] => Topic 2 [subcat] => Array ([0] => Array ([id] => 4 [pid] => 2 [cat] => Topic 4) [1] => Array ([id] => 13 [pid] => 2 [cat] => column 13 [subcat] => Array ([0] => Array ([id] => 14 [pid] => 13 [cat] => 14 ))))) [2] => Array ([id] => 10 [pid] => 0 [cat] => Column 10 [subcat] => Array ([0] => Array ([id] => 11 [pid] => 10 [cat] => column 11 [subcat] => Array ([0] => Array ([id] => 12 [pid] => 11 [cat] => column 12 ))))))

If you need such an assembly format or the format to facilitate subsequent processing, you can try this method.