PHP Infinite Pole Classification implementation (without recursion), PHP recursive _php tutorial

PHP Infinite Pole Classification implementation (without recursion), PHP recursion

Infinite pole classification is often used in development, for example: Department structure, article classification. The difficulty with infinite pole classification is "output" and "query", for example

• Export the article category to
  list form;
  • Find the articles that are included in all categories under Category A.

  1. Principle of implementation

  This article introduces several common methods of realizing the idea of infinite class classification, and has advantages and disadvantages. "Improved pre-sequence traversal tree" data structure, easy to output and query, but in the mobile classification and general understanding is somewhat complex.

  2. Data structure

  ID	FID	title
  1	0	China
  2	1	Jiangsu
  3	1	Anhui
  4	8	Jiangyin
  5	3	Wuhu
  6	3	Hefei
  7	3	Bengbu
  8	2	Wuxi

  
    
       1, 'fid'=>0, 'title' => '中国'),         array('id'=>2, 'fid'=>1, 'title' => '江苏'),        array('id'=>3, 'fid'=>1, 'title' => '安徽'),        array('id'=>4, 'fid'=>8, 'title' => '江阴'),        array('id'=>5, 'fid'=>3, 'title' => '芜湖'),        array('id'=>6, 'fid'=>3, 'title' => '合肥'),        array('id'=>7, 'fid'=>3, 'title' => '蚌埠'),        array('id'=>8, 'fid'=>8, 'title' => '无锡')    );?>

  A classification tree is formed by the level "concatenation" between the categories through the parent class ID (FID). It is worth noting in tandem that the FID of categorical a cannot be the ID of its subclass.

  In the use of this data structure to output the most commonly used algorithm is "recursive", familiar with the PHP language friends must know that PHP is not good at recursion, and the number of recursion is limited (about 100 times, due to operating system and configuration vary).

  Since all recursion can be implemented using loops, a function of "infinite Class" classification is written according to PHP language features, which is more efficient than recursive implementations.

  3. Output UL List form

  Export the above data to the following HTML

  
    
       
       
   
        
   江苏 
         
   
          
   无锡 
           
   
            
   江阴 
   
           
   
   
         
   
   
        
   安徽 
         
   
          
  芜湖
   
          
  合肥
   
          
  蚌埠
   
         
   
   
       

  This HTML structure is handy for front-end use (using JavaScript and CSS to construct collapsible trees). The specific implementation procedure is as follows:

  4. Output Option List form

  江苏    无锡        江阴安徽    芜湖    合肥    蚌埠

  The specific implementation procedure is as follows:

  
       ' . Str_repeat ("", $op [' depth '] * 4). $op [' title '].    ' <;/option> '; }?><;/select>5. Find all subclasses of a class
       6. Find all the parent classes for 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] = = $id) {array_sp                        Lice ($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 >) return $html _left;    } unset ($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; $i-) {Array_unshift ($st            Ack, $child [$id] [$i]);        } $flag = true;            if ($id! = $fid && $node &&!isset ($added [$id])) {$node [' depth '] = $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 [' FID '], $node, 1);             Break       }} if (count ($child [$node [' fid ']] = = 0) {$child [$node [' fid ']] =                    Null                $depth--;        }} array_shift ($stack);        } $loop + +;    if ($loop >) return $options;    } unset ($child);    Unset ($obj); return $options;}? >PHP recursion problem (infinite pole classification)foreach itself is the equivalent of a judge, when the $arr array is not empty, foreach iterates and recursively accesses the child nodes, but for the leaf nodes, the $arr array is empty and will not be foreach at this point, and return directly. Got it?PHP recursion problem, want to display the data in the style of infinite pole classificationFirst, the JSON is decoded into the array, using the Json_decode function to note that the second parameter must be added otherwise he will return an object. The next step is to recursion. This is one of the simplest recursion as long as it is traversed individually.The following is the complete code:$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>!--? php}?--></select> 
   The above code has been tested as follows 
   
   
   
     
   
   
   
  http://www.bkjia.com/phpjc/831802.html  www.bkjia.com   True  http://www.bkjia.com/phpjc/831802.html  techarticle  php the implementation of the Infinite Pole classification (no recursion is used), PHP Recursive infinite Pole classification is often used in development, for example: Department structure, article classification. The difficulty with infinite pole classification is the output and the search ...  
   
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