PHP unlimited classification implementation (no recursion is used)

Unlimited classification is often used in development, such as Department structure and document classification. The difficulty of an unlimited classification lies in output and query. For example, the document category is output to the ul list form, and the article contained in all categories under category A is searched. 1. Implementation Principles: several common implementations are introduced in the article "how to implement an unlimited classification ".

Unlimited classification is often used in development, such as Department structure and document classification. The difficulty of unlimited classification lies in output and query. For example, the document category is output in the ul list form, and the article contained in all categories under category A is searched. 1. Implementation principles I have introduced several common practices in "Unlimited classification implementation ideas"

UnlimitedLevelCategoryOften used during developmentUseFor example, Department structure and articleCategory.UnlimitedLevelCategoryThe difficulty lies in "output" and "query", for example

• PostCategoryThe output is
  List form;
  • SearchCategoryAllCategoryIncluded articles.
  1.ImplementationPrinciple

  In 《UnlimitedLevelCategoryImplementationThis article introduces several commonImplementationMethods have their own advantages and disadvantages. The data structure of "improved forward traversal Tree" facilitates output and query,CategoryIt is somewhat complicated than conventional 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 ');?>

  VariousCategoryThrough the parent class id (that is, fid) to formCategoryTree. Note the following points during the series:CategoryThe fid of A cannot be the id of its subclass.

  InUseThe most common algorithm for outputting such data structures is "recursion". friends familiar with PHP certainly know that PHP is not good at recursion and has limited recursion times (about 100 times, operating System and configuration vary ).

  Because all recursion is acceptableUseLoopImplementationAccording to the characteristics of the PHP language, this article compiled a set ofUnlimitedLevel"CategoryCompared with recursionImplementationHigher efficiency

  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 on the front endUse(UseJavaScript and CSS to construct a foldable tree) is very convenient. DetailsImplementationThe procedure is as follows:

  4. Output option List format

      Jiangsu    Wuxi    Jiangyin    Anhui Province    Wuhu    Hefei    Bengbu

  DetailsImplementationThe procedure is as follows:

  
       '. Str_repeat ("", $ op ['Demo'] * 4). $ op ['title'].' <;/option> ';}?> <;/Select>5. FindCategoryAll subclasses
       6. FindCategoryAll parent classes
       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 ;}?>