PHP Infinitus classification implementation (do not use recursion), php recursion _ PHP Tutorial

PHP Infinitus classification implementation (do not use recursion), php recursion. PHP Infinitus classification implementation (no recursion), php recursion Infinitus classification is often used in development, such as: department structure, document classification. The difficulty of Infinitus classification lies in the implementation of outputting and querying PHP Infinitus classification (no recursion is used), and php recursion

Infinitus classification is often used in development, such as department structure and document classification. The difficulties of Infinitus classification are "output" and "query", for example

• Output the document category
  List form;
  • Search for articles contained in all categories under Category.
  1. implementation principle

  Several common implementation methods are introduced in the article "how to implement an unlimited classification", which have their own advantages and disadvantages. The data structure of "improved forward traversal tree" is easy to output and query, but it is complicated in terms of mobile classification and general understanding.

  2. Data structure

  Id	Fid	Title
  1	0	China
  2	1	Jiangsu
  3	1	Anhui province
  4	8	Jiangyin
  5	3	Wuhu
  6	3	Hefei
  7	3	Bengbu
  8	2	Wuxi

  
      1, 'fid' => 0, 'title' => 'China'), array ('id' => 2, 'fid' => 1, 'title' => 'Jiangsu '), array ('id' => 3, 'fid' => 1, 'title' => 'Anhui '), array ('id' => 4, 'fid' => 8, 'title' => 'jiangyin '), array ('id' => 5, 'fid' => 3, 'title' => 'wuhu '), array ('id' => 6, 'fid' => 3, 'title' => 'Hefei '), array ('id' => 7, 'fid' => 3, 'title' => 'bengbu '), array ('id' => 8, 'fid' => 8, 'title' => 'Wuxi ');?>

  Each category is connected by its parent class id (fid) to form a classification tree. It is worth noting that the fid of classification A cannot be the id of its subclass.

  When using this data structure for output, the most common algorithm is "recursion". friends familiar with the PHP language certainly know that PHP is not good at recursion and has a limited number of recursion times (about 100 times, operating system and configuration vary ).

  Since all recursion functions can be implemented cyclically, this article has compiled a set of functions for "infinite" classification based on the characteristics of PHP language, which is more efficient than recursive implementation.

  3. output ul List format

  Output the above data as the following HTML

  
      
      
   
       
   
  Jiangsu
   
        
   
         
   
  Wuxi
   
          
   
           
   
  Jiangyin
   
   
          
   
   
        
   
   
       
   
  Anhui province
   
        
   
         
  Wuhu
   
         
  Hefei
   
         
  Bengbu
   
        
   
   
      

  This HTML structure is very convenient for front-end use (using JavaScript and CSS to construct a foldable tree. The specific implementation procedure is as follows:

  4. output option List format

  JiangsuWuxiJiangyinAnhui provinceWuhuHefeiBengbu

  The specific implementation procedure is as follows:

  
       '. Str_repeat ("", $ op ['demo'] * 4). $ op ['title'].' <;/option> ';}?> <;/Select>5. search for all subclasses of a category
       6. search for all parent classes of a category
       7. related functions
       = 0; $ I --) {$ node = $ data [$ I]; if ($ node ['fid'] = $ fid) {array_splice ($ data, $ I, 1); $ result [] = $ node ['id']; $ cids [] = $ node ['id']; $ flag = true ;}}} $ fids = $ cids;} while ($ flag = true); return $ result;} function get_tree_parent ($ data, $ id) {$ result = array (); $ obj = array (); foreach ($ data as $ node) {$ obj [$ node ['id'] = $ node ;} $ value = isset ($ obj [$ id])? $ Obj [$ id]: null; while ($ value) {$ id = null; foreach ($ data as $ node) {if ($ node ['id'] = $ value ['fid']) {$ id = $ node ['id']; $ result [] = $ node ['id']; break ;}} if ($ id = null) {$ result [] = $ value ['fid'];} $ value = isset ($ obj [$ id])? $ Obj [$ id]: null;} unset ($ obj); return $ result;} function get_tree_ul ($ data, $ fid) {$ stack = array ($ fid ); $ child = array (); $ added_left = array (); $ added_right = array (); $ html_left = array (); $ html_right = array (); $ obj = array (); $ loop = 0; foreach ($ data as $ node) {$ pid = $ node ['fid']; if (! Isset ($ child [$ pid]) {$ child [$ pid] = array ();} array_push ($ child [$ pid], $ node ['id']); $ obj [$ node ['id'] = $ node;} while (count ($ stack)> 0) {$ id = $ stack [0]; $ flag = false; $ node = isset ($ obj [$ id])? $ Obj [$ id]: null; if (isset ($ child [$ id]) {$ cids = $ child [$ id]; $ length = count ($ cids); for ($ I = $ length-1; $ I >=0; $ I --) {array_unshift ($ stack, $ cids [$ I]);} $ obj [$ cids [$ length-1] ['islastchild '] = true; $ obj [$ cids [0] ['isfirstchild '] = true; $ flag = true;} if ($ id! = $ Fid & $ node &&! Isset ($ added_left [$ id]) {if (isset ($ node ['isfirstchild ']) & isset ($ node ['islastchild']) {$ html_left [] ='';} Else if (isset ($ node ['isfirstchild']) {$ html_left [] ='';} Else if (isset ($ node ['islastchild']) {$ html_left [] ='';} Else {$ html_left [] ='';} $ Html_left [] = ($ flag = true )? "{$ Node ['title']}":"{$ Node ['title']}"; $ Added_left [$ id] = true;} if ($ id! = $ Fid & $ node &&! Isset ($ added_right [$ id]) {$ html_right [] = ($ flag = true )? '':''; $ Added_right [$ id] = true;} if ($ flag = false) {if ($ node) {$ cids = $ child [$ node ['fid']; for ($ I = count ($ cids)-1; $ I >=0; $ I --) {if ($ cids [$ I] ==$ id) {array_splice ($ child [$ node ['fid'], $ I, 1); break ;}} if (count ($ child [$ node ['fid']) = 0) {$ child [$ node ['fid'] = null ;}} array_push ($ html_left, array_pop ($ html_right); array_shift ($ stack) ;}$ loop ++; if ($ loop> 5000) return $ html_l Eft;} unset ($ child); unset ($ obj); return implode ('', $ html_left);} function get_tree_option ($ data, $ fid) {$ stack = array ($ fid); $ child = array (); $ added = array (); $ options = array (); $ obj = array (); $ loop = 0; $ depth =-1; foreach ($ data as $ node) {$ pid = $ node ['fid']; if (! Isset ($ child [$ pid]) {$ child [$ pid] = array ();} array_push ($ child [$ pid], $ node ['id']); $ obj [$ node ['id'] = $ node;} while (count ($ stack)> 0) {$ id = $ stack [0]; $ flag = false; $ node = isset ($ obj [$ id])? $ Obj [$ id]: null; if (isset ($ child [$ id]) {for ($ I = count ($ child [$ id])-1; $ I> = 0; $ I --) {array_unshift ($ stack, $ child [$ id] [$ I]);} $ flag = true;} if ($ id! = $ Fid & $ node &&! Isset ($ added [$ id]) {$ node ['dest'] = $ depth; $ options [] = $ node; $ added [$ id] = true ;} if ($ flag = true) {$ depth ++;} else {if ($ node) {for ($ I = count ($ child [$ node ['fid'])-1; $ I >=0; $ I --) {if ($ child [$ node ['fid'] [$ I] ==$ id) {array_splice ($ child [$ node ['fid'], $ I, 1); break; }}if (count ($ child [$ node ['fid']) = 0) {$ child [$ node ['fid'] = null; $ depth -- ;}} array_shift ($ stack) ;}$ loo P ++; if ($ loop> 5000) return $ options;} unset ($ child); unset ($ obj); return $ options ;}?>Php recursion (Infinitus classification)Foreach itself is equivalent to judgment. when the $ arr array is not empty, foreach will traverse and recursively access the child node, but for the leaf node, the $ arr array is empty, it will not be foreach at all, and return directly at this time. Understand?Php recursion problem, want to display the data according to the Infinitus classification styleFirst, decode the json into an array. use the json_decode function to add the second parameter. Otherwise, it will return an object. The next step is recursive. This is the simplest recursion. you only need to traverse them one by one.The complete code is as follows:$ Data = json_decode ($ str, true); $ options = getChildren ($ data); function getChildren ($ parent, $ deep = 0) {foreach ($ parent as $ row) {$ data [] = array ("id" => $ row ['id'], "name" => $ row ['name'], "pid" => $ row ['parentid'], 'Deep '=> $ deep); if ($ row ['childs']) {$ data = array_merge ($ data, getChildren ($ row ['Childs '], $ deep + 1) ;}return $ data ;}?>
      
       
       </Option>
       </Select>
  The above code has passed the test as follows:
  
  
  
  
  Recursive (no recursion is used). php recursive Infinitus classification is often used in development, such as department structure and document classification. The difficulty of Infinitus classification lies in output and query...