使用递归生成嵌套数组

Question

我有一个这样的输入数组

$input = array(
    array(
        "relation"=>"OR"
    ),
    array(
        "color"=> 'green'
    ),
    array(
        "color"=> 'yellow'
    ),
    array(
        "relation"=>"AND"
    ),
    array(
        "color"=>"black"
    ),
    array(
        "color"=>"orange"
    ),
    array(
        "relation"=>"OR"
    ),
    array(
        "color"=>"blue"
    ),
     array(
        "color"=>"violet"
    ),
);

我想要达到的输出是这个

$output = array(
    'relation' => 'OR',
    array(
        "color" => 'green'
    ),
    array(
        "color" => 'yellow'
    ),
    array(
        "relation" => "AND",
        array(
            "color" => "black"
        ),
        array(
            "color" => "orange"
        ),
        array(
            "relation" => "OR",
            array(
                "color" => "blue"
            ),
            array(
                "color" => "violet"
            ),
        )
    )
);

我相信我需要做递归函数来处理这个

我有这个，但只适用于一个级别

function generate_nested_array($array, $nested_tax_query = array(), $target_index = 0)
{

        //the first element is always the relation
        $nested_tax_query['relation'] = $array[0]['relation'];
        // unset the first element as it is not needed anymore
        unset($array[0]);
    
    
        $len = count($array);
        // reindex the array
        $array = array_values($array);
    
    
        foreach ($array as $element_key => $element) {
            if (isset($element['relation'])) {
                $target_index = $element_key;
                break;
            }
        }
    
    
        // put everything below the target index into the target index and leave the rest as it is
        for ($i = 0; $i < $len - 1; $i++) {
            if ($i < $target_index) {
                $nested_tax_query[] = $array[$i];
            } else {
                $nested_tax_query[$target_index][] = $array[$i];
            }
        }
    
        // last item in the nested array
        $len_nested  = count($nested_tax_query);
    
        // last item in the in the nested array
        $last_item_in_nested_array  = $nested_tax_query[$len_nested - 2]; 
    
    
        return $nested_tax_query;
    }

我的做法正确吗？

Answer 1

你说得对，递归是个好方法。首先，我建议按原样保留原始数组，这样您就不必考虑在处理它时会经历的各种修改。要将其部分标记为已处理，您可以使用索引（如您的

target_index

参数所建议的那样）或将数组的切片传递给递归调用。

我认为你很接近，你只需要在函数末尾对数组的其余部分做一些事情（如果有更多的元素要处理）。