我这里有这段代码,它给了我想要的结果,一个格式良好的值树。
$todos = $this->db->get('todos'); //store the resulting records
$tree = array(); //empty array for storage
$result = $todos->result_array(); //store results as arrays
foreach ($result as $item){
$id = $item['recordId'];
$parent = $item['actionParent'];
$tree[$id] = isset($tree[$id]) ? $item + $tree[$id] : $item;
$tree[$parent]['_children'][] = &$tree[];
}
echo '<pre>';
print_r($tree);
echo '</pre>';
当我把foreach中的代码放入这样的函数中时,我得到一个空数组。我错过了什么?
function adj_tree($tree, $item){
$id = $item['recordId'];
$parent = $item['actionParent'];
$tree[$id] = isset($tree[$id]) ? $item + $tree[$id] : $item;
$tree[$parent]['_children'][] = &$tree[];
}
$todos = $this->db->get('todos'); //store the resulting records
$tree = array(); //empty array for storage
$result = $todos->result_array(); //store results as arrays
foreach ($result as $item){
adj_tree($tree, $item);
}
echo '<pre>';
print_r($tree);
echo '</pre>';
最简单的方法是通过引用将$tree
传递给函数。考虑更改代码中的以下行
function adj_tree($tree, $item)
至
function adj_tree(&$tree, $item)
这是因为在您的代码中,$tree
作为原始$tree
的副本在函数adj_tree
中传递。通过引用传递时,会传递原始引用,并且函数adj_tree
对其所做的更改会在调用后反映出来。
第二个(不是首选)选项是让您的函数返回修改后的树,因此您的函数将如下所示:
function adj_tree($tree, $item) {
$id = $item['recordId'];
$parent = $item['actionParent'];
$tree[$id] = isset($tree[$id]) ? $item + $tree[$id] : $item;
$tree[$parent]['_children'][] = &$tree[];
return $tree; // this is the line I have added
}
你的foreach
循环将是这样的:
foreach ($result as $item){
$tree = adj_tree($tree, $item);
}
现在,函数正在制作{$tree}的本地副本,对其进行编辑,然后在函数关闭时丢弃该副本。
你有两个选择:
1) 返回{$tree}的本地副本,并将其分配给全局副本。
function adj_tree($tree, $item){
$id = $item['recordId'];
$parent = $item['actionParent'];
$tree[$id] = isset($tree[$id]) ? $item + $tree[$id] : $item;
$tree[$parent]['_children'][] = &$tree[];
return $tree;
}
//...
foreach ($result as $item){
$tree = adj_tree($tree, $item);
}
2) 通过引用传递数组,并在函数中编辑全局版本。
function adj_tree(&$tree, $item){
$id = $item['recordId'];
$parent = $item['actionParent'];
$tree[$id] = isset($tree[$id]) ? $item + $tree[$id] : $item;
$tree[$parent]['_children'][] = &$tree[];
}
试试这个:
function adj_tree($tree, $item){
global $tree;
// ...
或
function adj_tree(&$tree, $item){