从我的数组树中添加前缀“>”

Question

Array
(
[0] => Array
    (
        [id] => 39
        [parent_id] => 0
        [sku] => Parent
    )

[1] => Array
    (
        [id] => 40
        [parent_id] => 39
        [sku] => Child of parent id 39
    )

[2] => Array
    (
        [id] => 41
        [parent_id] => 40
        [sku] => Child of child id 40
    )

[3] => Array
    (
        [id] => 42
        [parent_id] => 40
        [sku] => Another child of child id 40
    )

[4] => Array
    (
        [id] => 43
        [parent_id] => 39
        [sku] => Another child of parent id 39
    )
etc..
)

我这里有一个关联数组，它基本上是 parent - child 关系。网上有很多关于如何构建树的示例，对我帮助很大。但现在我只想将我的数组格式化为这样的格式：

> Parent                               --> first prefix ">"
    >> Child of parent id 39           --> added two ">" prefixes
        >>> Child of child id 40       --> added three ">" prefixes
        >>> Another child of child id 40
    >> Another child of parent id 39
and so on..

更新：这就是我现在构建树的方式：

function pdf_content($data, $parentId = 0)
{
    $str = '';

    foreach ($data as $row) {
        if ($row['parent_id'] == $parentId) {
            $str .= '<li>';
            $str .= $row['sku'];
            $str .= pdf_content($data, $row['id']);
            $str .= '</li>';
        }
    }

    if ($str) {
        $str = "<ol class='dashed'>" . $str . '</ol>';
    }
    return $str;
}
// this is using the ol list style.

所以首先 children 必须得到它的 parent 并附加前缀“>”。我已经有了构建树的代码，但是将它格式化为这样的东西让我卡在树上。

Answer 1

要添加前缀，请使用带有传递参数 $prefix = '>' 的递归函数，如果找到子项，则连接 $prefix .= '>'，如果未找到子项，则传入您的函数，然后仅覆盖 $prefix = '>'

Answer 2

我认为应该这样做。

function pdf_content($items, $parentId = 0, $prefix = '>')
{
    $str = '';
    foreach ($items as $item) 
    {
       if ($item['parent_id'] == $parentId) {
           $str .= '<li>';
           $str .= $prefix.$item['sku'];
           $str .= pdf_content($items, $item['id'], $prefix.'>');
           $str .= '</li>';
       }
    }
    if ($str) {
        $str = "<ol class='dashed'>" . $str . '</ol>';
    }
    return $str;
}

$string = pdf_content($array);

这就是我得到的输出 -

>Parent
    >>Parent 39
        >>>Parent 40
        >>>Parent 40
    >>Parent 39

从我的数组树中添加前缀“>”

Adding prefix '>' from my array tree

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