


Hierarchical processing code for infinite hierarchical data in PHP array_PHP tutorial
/**
* Create a parent node tree array
* Parameters
* $ar array, data organized in adjacency list
* $id The subscript or associated key name as the primary key in the array
* $pid The subscript or associated key name as the parent key in the array
* Returns a multi-dimensional array
**/
function find_parent($ar, $id='id', $pid='pid') {
foreach($ar as $v) $t[$v[$id]] = $v;
foreach ($t as $k => $item){
if( $item[$pid] ){
if( ! isset($t[$item[$pid]]['parent'][$item[$pid]]) )
$t[$item[$id]]['parent'][$item[$pid]] =& $t[$item[$pid]];
$t[$k]['reference'] = true;
}
}
return $t;
}
/**
* Create a tree array of child nodes
* Parameters
* $ar array, data organized in adjacency list
* $id The subscript or associated key name as the primary key in the array
* $pid The subscript or associated key name as the parent key in the array
* Returns a multi-dimensional array
**/
function find_child($ar, $id='id', $pid='pid') {
foreach($ar as $v) $t[$v[$id]] = $v;
foreach ($t as $k => $item){
if( $item[$pid] ) {
$t[$item[$pid]]['child'][$item[$id]] =& $t[$k];
$t[$k]['reference'] = true;
}
}
return $t;
}
示例:
$data = array(
array('ID'=>1, 'PARENT'=>0, 'NAME'=>'祖父'),
array('ID'=>2, 'PARENT'=>1, 'NAME'=>'父亲'),
array('ID'=>3, 'PARENT'=>1, 'NAME'=>'叔伯'),
array('ID'=>4, 'PARENT'=>2, 'NAME'=>'自己'),
array('ID'=>5, 'PARENT'=>4, 'NAME'=>'儿子')
);
$p = find_parent($data, 'ID', 'PARENT');
$c = find_child($data, 'ID', 'PARENT');
上面两种方法是将所有节点按id平摊到一个数组中,然后找到他们的 parent 或 children ,通过引用将 平摊的元素挂接到 parent 、children 下,
但被引用的元素依然存在于平摊的数组中,因此,在实际应用时,最好标记那些被引用的元素,以避免以他们为根开始遍历,导致重复。
foreach ($p as $key => $item) {
if($item['reference']) continue;
print_r($item);
}
foreach ($c as $key => $item) {
if($item['reference']) continue;
print_r($item);
}
递归法,PHP 数组元素被删除后,数组游标会归零,因此在遍历过程中一些已经找到 “归宿” 的元素也不得不留在数组中,无法缩减后继元素的搜索范围:
$mylist = array(array( 'parent_id'=>0,'id'=>1),
array( 'parent_id'=>0,'id'=>2),
array( 'parent_id'=>0,'id'=>3),
array( 'parent_id'=>2,'id'=>4),
array( 'parent_id'=>2,'id'=>5),
array( 'parent_id'=>3,'id'=>6),
array( 'parent_id'=>3,'id'=>7),
array( 'parent_id'=>4,'id'=>8),
array( 'parent_id'=>5,'id'=>9),
array( 'parent_id'=>5,'id'=>10)
);
function _findChildren($list, $p_id){ //数据层级化,
$r = array();
foreach($list as $id=>$item){
if($item['parent_id'] == $p_id) {
$length = count($r);
$r[$length] = $item;
if($t = $this->_findChildren($list, $item['id']) ){
$r[$length]['children'] = $t;
}
}
}
return $r;
}
print_r(_findChildren($mylist, 0));

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