Question

Given an array:

$arrData = array(
 0 => array (
   'uid'   => 1,
   'name'  => 'label',
   'open'  => 0,
   'close' => 9
 ),
 1 => array (
   'uid'   => 2,
   'name'  => 'label',
   'open'  => 1,
   'close' => 2
 ),
 2 => array (
   'uid'   => 3,
   'name'  => 'label',
   'open'  => 3,
   'close' => 8
 ),
 3 => array (
   'uid'   => 4,
   'name'  => 'label',
   'open'  => 4,
   'close' => 5
 ),
 4 => array (
   'uid'   => 5,
   'name'  => 'label',
   'open'  => 6,
   'close' => 7
 )
);

Which represents this structure:

<label>     [0,9]
 <label />  [1,2]
 <label>    [3,8]
  <label /> [4,5]
  <label /> [6,7]
 </label>
</label>

I am trying to get to an array that results in this format:

$arrNesting = array(
 0=>array(
   'item'    => array('uid'=>1, 'name'=>'label', 'open'=>0, 'close'=>9),
   'children' => array(
     0=>array(
       'item'     => array('uid'=>2, 'name'=>'label', 'open'=>1, 'close'=>2),
       'children' => array()
     ),
     1=>array(
       'item'     => array('uid'=>3, 'name'=>'label', 'open'=>3, 'close'=>8),
       'children' => array(
         0=>array(
           'item'     => array('uid'=>2, 'name'=>'label', 'open'=>4, 'close'=>5),
           'children' => array()
         ),
         1=>array(
           'item'     => array('uid'=>3, 'name'=>'label', 'open'=>6, 'close'=>7),
           'children' => array()
         )
       )
     )
   )
 )
);

via a function call like this:

// $arrData: Source Data with keys for denoting the left and right node values
// 'open': the key for the left node's value
// 'close': the key for the right node's value
$arrNested = format::nestedSetToArray( $arrData, 'open', 'close' );

So far, I’ve tried this format, assuming the $arrData values will always be in left value ascending order. The uid values ‘happen’ to also be in order, but are not relied upon to be so:

public static function nestedSetToArray( $arrData = array(), $openKey='open', $closeKey='close') {
// Hold the current Hierarchy
$arrSets = array();

// Last parent Index, starting from 0
$intIndex = 0;

// Last Opened and Closed Node Values, and maximum node value in this set
$intLastOpened = 0;
$intLastClosed = null;
$intMaxNodeNum = null;

// loop through $arrData
foreach( $arrData as $intKey=>$arrValues) {
  if( !isset( $arrSets[ $intIndex ] )) {
      // Create a parent if one is not set - should happen the first time through
      $arrSets[ $intIndex ] = array ('item'=>$arrValues,'children'=>array());
      $intLastOpened = $arrValues[ $openKey ];
      $intLastClosed = null; // not sure how to set this for checking 2nd IF below
      $intMaxNodeNum = $arrValues[ $closeKey ];
  } else {
      // The current item in $arrData must be a sibling or child of the last one or sibling of an ancestor
      if( $arrValues[ $openKey ] == $intLastOpened + 1) {
         // This is 1 greater then an opening node, so it's a child of it
      } else if( /* condition for sibling */ ) {
         // This is 1 greater than the intLastClosed value - so it's a sibling
      } else if( /* condition for sibling of ancestor */ ) {
         // This starts with a value greater than the parent's closing value...hmm
      }
  }
}

}

Any pointers to take this further would be appreciated.

Answer 1

This should works

$stack = array();
$arraySet = array();


foreach( $arrData as $intKey=>$arrValues) {
    $stackSize = count($stack); //how many opened tags?
    while($stackSize > 0 && $stack[$stackSize-1]['close'] < $arrValues['open']) {
            array_pop($stack); //close sibling and his childrens
            $stackSize--;
        }

    $link =& $arraySet;
    for($i=0;$i<$stackSize;$i++) {
        $link =& $link[$stack[$i]['index']]["children"]; //navigate to the proper children array
    }
    $tmp = array_push($link,  array ('item'=>$arrValues,'children'=>array()));
    array_push($stack, array('index' => $tmp-1, 'close' => $arrValues['close']));

}

return $arraySet;

I skip parametrized open and close tags but you can simply add it.

EDIT

What is happening here:

First the $stack is empty so we skip while().
Then we assign reference to $arraySet to the $link, because $stack is empty we push first element to $link which is reference to $arraySet. array_push()return 1 because this is the new length of$arraySet
Next we add an element to the$stackwhit values(‘index’ => 0, ‘close’ => 10)`

Next element:
Now $stack has 1 element, but $stack[0]['close'] is greater than $arrValues['open'] for element so we skip while.
Again we set reference to $arraySet to $link but now there is on element in $stack so we assign $link[$stack[0]['index']]["children"] reference to $link so now $link is pointing to $arraySet[0]["children"].
Now we push element to this children array. $tmp gives us size of this children array and we push proper element to the stack.

Next element:
It looks exactly like second one but at the beginning we pop one element from stack. So after this iteration on stack are two elements

('index' => 0, 'close' => 10)
('index' => 0, 'close' => 8)

Next element:
There is two element on stack but both have greater close attribute then $arrValues['open'] so we skip while loop. Then in navigation part:

• $link is pointing to $arraySet
• then to $arraySet[0]["children"]
• then to $arraySet[0]["children"][0]["children"]

And we push element to this array.
And so on…