PHP Recursive implementation of infinite-level classification tree

The infinite-level tree can be said to be a significant feature of the infinite-level column, and we'll look at two different ways to do it next.

I. Database design

CREATE TABLE ' bg_cate ' (' cate_id ' int () unsigned not NULL auto_increment, ' cate_parentid ' int (0) unsigned DEFAULT ' + ', ' C ' Ate_name ' varchar ' NOT NULL, ' Cate_intro ' varchar ($) Default NULL, ' Cate_order ' int (in) unsigned default ' 0 ', ' cate_ Icon ' varchar ' default null,primary KEY (' cate_id ') engine=myisam default Charset=utf8 auto_increment=34;----Export table Data ' bg_cate '--insert into ' bg_cate ' (' cate_id ', ' cate_parentid ', ' cate_name ', ' Cate_intro ', ' cate_order ', ' Cate_icon ') VALUES (4, 0, ' past events such as Wind ', ' record past ', 0, ' Icons/6.gif '), (5, 0, ' Boiled Three Kingdoms ', ' Wisdom of the Three Kingdoms ', 0, ' Icons/3.gif '), (2, 0, ' technical learning ', ' regular learning of some notes, welcome criticism. 。 ', 0, ' Icons/18.gif '), (3, 0, ' Life drops ', ' record Life drops ', 0, ' Icons/2.gif '), (6, 0, ' Gardenia Blossom ', ' Youth Infinity ', 0, ' Icons/8.gif '), (7, 0, ' holiday casual ', ' Leisurely, comfortable ', 0, ' Icons/24.gif '), (8, 2, ' HTML ', ' HTML learning ', 0, ' Icons/1.gif '), (9, 2, ' CSS ', ' CSS learning ', 0, ' Icons/1.gif '), (ten, 2, ' ph P ', ' PHP learning ', 0, ' Icons/18.gif '), (one, ten, ' PHP Basics ', ' php basics ', 0, ' Icons/1.gif '), (A., ' oop ', ' oop ', 0, ' icons/1.gif '), (+, ' php security ', ' Tell PHP security ', 0, ' Icons/1.gif '), (+, ten, ' Seagull Framework ', ' Seagull Framework ', 0, ' Icons/1.gif '), (2, ' JavaScript ', ' JavaScript learning ', 0, ' Icons/1.gif '), (16, 2, ' design mode ', NULL, 0, ' Icons/1.gif '), (17, 2, ' Software engineering ', ' Software Engineering Learning ', 0, ' Icons/1.gif '), (18, 3, ' Xiamen life ', ' Xiamen life ', 0, ' Icons/8.gif '), (19, 3, ' university Life ', ' university Life ', 0, ' Icons/8.gif '), (20, 3, ' childhood life ', ' childhood ', 0, ' Icons/15.gif '), (21, 19, ' learning ' Learning ', 0, ' Icons/1.gif '), (22, 19, ' movement ', ' sport ', 0, ' Icons/16.gif '), (23, 19, ' travel ', ' travel ', 0, ' Icons/24.gif '), (24, 22, ' volleyball ', ' Volleyball ', 0, ' Icons/9.gif '), (25, 22, ' basketball ', ' basketball ', 0, ' Icons/9.gif '), (26, 22, ' Badminton ', ' badminton ', 0, ' Icons/9.gif '), (27, 22, ' table tennis ', ' ping Pong Ball ', 0, ' icons/9.gif ');

Two. Take the data to the database and put it into the array.

Require_once './classes/mydb.php '; $con = Mydb::singleton (); $sql = <<<sql   select * from Bg_cate catesql;$ data = $con->getall ($sql);//print_r ($data);

Database operations I'm using the Pear class library.
The final $data data format is as follows:

Array (   [0] = = Array       (           [cate_id] = 4           [Cate_parentid] = 0           [Cate_name] = past events such as wind           [ Cate_intro] [           cate_order] = 0           [Cate_icon] = icons/6.gif       )   [1] = = Array       ( C13/>[CATE_ID] + 5           [Cate_parentid] = 0           [cate_name] + boiled Three Kingdoms           [Cate_intro] = grade three Wisdom           [ Cate_order] + 0           [Cate_icon] = Icons/3.gif       )

Three. Convert the data from the previous step to a tree-shaped array
The code is as follows:

function Gettree ($data, $pId) {$tree = "; foreach ($data as $k + = $v) {  if ($v [' cate_parentid '] = = $pId)  {        // Father found son   $v [' cate_parentid '] = Gettree ($data, $v [' cate_id ']);   $tree [] = $v;   Unset ($data [$k]);}  return $tree;} $tree = Gettree ($data, 0);

The data format for the last output $tree is:

Array ([0] = = Array ([cate_id] = 4 [Cate_parentid] = [cate_name] = = Go to  Things like wind [Cate_intro] and record the past [cate_order] = 0 [Cate_icon] = icons/6.gif) [1]           = = Array ([cate_id] = 5 [Cate_parentid] = [Cate_name] = boiled Three Kingdoms [Cate_intro] = grade three wisdom [cate_order] = 0 [Cate_icon] = Icons/3.gif) [2] = ARR Ay ([cate_id] = 2 [Cate_parentid] = Array ([0] = A                           Rray ([cate_id] = 8 [Cate_parentid] =                           [Cate_name] + html [cate_intro] = HTML Learning [Cate_order] = 0 [Cate_icon] = icons/1.gif)

Four. Converting a tree-shaped array to HTML
The code is as follows:

function prochtml ($tree) {$html = '; foreach ($tree as $t) {  if ($t [' cate_parentid '] = = ')  {   $html. = "<li& Gt {$t [' cate_name ']}</li> ';  }  else  {   $html. = "<li>". $t [' Cate_name '];   $html. = prochtml ($t [' Cate_parentid ']);   $html = $html. " </li> ";  }} Return $html? ' <ul> '. $html. ' </ul> ': $html;} echo prochtml ($tree);

The code format for the output HTML is:

<ul><li> past events such as wind </li><li> boiling water </li><li> Technical Learning  <ul>   <li>html </li>   <li>css</li>   <li>php    <ul>     <li>php Basics </li>     <li>oop</li>     <li>php Safety </li>

Five. Code integration

function Gettree ($data, $pId) {$html = "; foreach ($data as $k + = $v) {  if ($v [' cate_parentid '] = = $pId)  {        // Father found his son   $html. = "<li>". $v [' Cate_name '];   $html. = Gettree ($data, $v [' cate_id ']);   $html = $html. " </li> ";  }} Return $html? ' <ul> '. $html. ' </ul> ': $html;} Echo gettree ($data, 0);

Six. Add CSS style

The second is a very, very brief introduction from the open Source website.

<?php function GenTree5 ($items) {foreach ($items as $item) $items [$item [' pid ']][' son '] [$item [' id ']] = &amp     ; $items [$item [' id ']]; return Isset ($items [0][' son '])? $items [0][' son ']: Array ();  /** * Format data into a tree structure * @author xuefen.tong * @param array $items * @return array */function genTree9 ($items) {$tree = Array (); Well-formatted tree foreach ($items as $item) if (Isset ($items [$item [' pid]]) $items [$item [' pid ']][' son '] [] = &        amp; $items [$item [' id ']];    else $tree [] = & $items [$item [' id ']]; return $tree;} $items = Array (1 = = Array (' id ' = = 1, ' pid ' = 0, ' name ' = ' Jiangxi '), 2 = = Array (' id ' = = 2, ' pid ' =& Gt  0, ' name ' = ' Heilongjiang Province '), 3 = = Array (' id ' = 3, ' pid ' = = 1, ' name ' = ' Nanchang '), 4 = = Array (' id ' = = 4, ' pid ' = 2, ' name ' = ' Harbin '), 5 = = Array (' id ' = 5, ' pid ' = = 2, ' name ' = ' Jixi '), 6 = = Array ( ' id ' = 6, ' pid ' = 4, ' name ' = ' Xiangfang District '), 7 = ArraY (' id ' = = 7, ' pid ' = + 4, ' name ' = ' Nangang '), 8 = = Array (' id ' = = 8, ' pid ' = 6, ' name ' = ' and Hing Road '), 9 = = Array (' id ' = = 9, ' pid ' = + 7, ' name ' = ' + ' West Dazhi Street '), ' ten ' = ' array ' (' id ' = ' = ', ' pid ' = ' 8 ', ' name ' =& Gt  ' Northeast Forestry University '), one-by-one and array (' id ' = = ', ' pid ' = 9, ' name ' = ' Harbin Institute of Technology '), and array (' id ' = ' + ', ' pid ') + 8, ' name ' = ' harbin Normal University '), and the array (' id ' = ' + ', ' pid ' = 1, ' name ' = ' Ganzhou '), + = Array (    ' id ' = +, ' pid ' = ' + ', ' name ' = ' Gan County '), and the array (' id ' = +, ' pid ' = ' + '), ' name ' = ' Yudu County '), + = array (' id ' = ' + ', ' pid ' = ' + ', ' name ' = ' Mao town '), ' + ' array ' (' id ' = ' = ', ' pid ' = ', ' Nam E ' = ' Ota township '), the array (' id ' = ' + ', ' pid ' = + ', ' name ' = ' righteousness source village '), + = array (' id ' = ' p ') ID ' = +, ' name ' = ' Shang Ba village '), echo "<pre>";p Rint_r (GenTree5 ($items));p Rint_r (GenTree9 ($items)); The latter output format, the former similar, but the array key value is not the same, but does not affect the data structure/*array ([0] = = Array ([id] = 1 [PID] + 0 [name] + Jiangxi [son] + = array ([0] = = Array ([id] = 3 [P                    ID] + 1 [name] = Nanchang) [1] = = Array                        ([id] [PID] + 1 [name] = = Ganzhou                                    [Son] = array ([0] = = Array ([id] = [p ID] = [name] = Gan County [son] = Arr                                        Ay ([0] = = Array        ([id] = 16                                                    [PID] = [name] + Mao Dian Zhen                                                        [son] = = Array (                                                            [0] = = Array (  [id] = [pid] =                                                            [Name] * + Righteousness Source Village                                                            ) [1] = = Array                                            ([id] = 19                [PID] [[Name] = + Shangba Village                                                 )                                                         )                                                ) [1] = = Array                                                    ([id] = 17                                                [PID] = [name] = Ota Township                                 )                                             )                                     )                                         [1] = = Array ([id] = 15                                    [PID] [name] = = Yudu County)))) [1] = = Array ([id] = 2                    [PID] = 0 [name] = Heilongjiang Province [son] + array ([0] = = Array                        ([id] = 4 [PID] + 2 [name] = + Harbin City                                [Son] = array ([0] = = Array                                    ([ID] + 6 [pid] = 4                                        [name] = = Xiangfang District [son] = Array                                                ([0] = = Array (                          [id] = 8 [PID] + 6                      [Name] = + Hing Road [son] = = Array                                                            ([0] = = Array                                                            ([id] = 10                                                            [PID] = 8                                                            [Name] = Northeast Forestry University                                                            ) [1] = = Array                                                            ([id] = 12 [PID] = 8 [n              AME] =                                               Harbin Normal University)                                         )                                             )                                )) [1] = = Array                                    ([ID] + 7 [PID] = 4                                        [Name] = Nangang District [son] + Array                                            ([0] = = Array (                                            [id] = 9 [PID] + 7                                                [Name] = West Big Straight Street [son] + Array     (                                           [0] = = Array (                                                    [id] = [pid] = 9                                                     [Name] = Harbin Institute of Technology                                             )                                                 )                             )                                         )                                 )                         )) [1] = = Array ([id] = 5 [PID] = 2 [name] = Jixi))) */

It can be seen that the second kind of code only uses 5 lines of code to achieve an infinite class of classification tree, it is worth everyone's reference and learning.

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