PHP实现为多维数组的每个子数组添加层级（level）字段

To add a level key to each node (subarray with id/parentid) in your nested array, you can use a recursive function that traverses the hierarchy and assigns the appropriate depth level. Here's how to do it in PHP:

Step-by-Step Code Implementation #

function addLevelToNodes(&$nodes, $level = 1) {
    foreach ($nodes as &$node) {
        // Check if we're dealing with a node (has an 'id' key)
        if (is_array($node) && isset($node['id'])) {
            // Assign the current level to this node
            $node['level'] = $level;
            
            // Look for any nested arrays containing child nodes
            foreach ($node as &$childCollection) {
                if (is_array($childCollection)) {
                    // Recursively process child nodes with incremented level
                    addLevelToNodes($childCollection, $level + 1);
                }
            }
        }
    }
}

How to Use This Function #

• Modify the array in place:

  // Your original multidimensional array
  $originalArray = [
      [
          'id' => 1,
          'parentid' => null,
          [
              'id' => 101,
              'parentid' => 1
          ]
      ],
      [
          'id' => 2,
          'parentid' => null,
          [
              'id' => 161,
              'parentid' => 2,
              'children' => [
                  [
                      'id' => 300,
                      'parentid' => 161
                  ]
              ]
          ]
      ]
  ];
  
  // Apply the function to add levels
  addLevelToNodes($originalArray);
  

• Keep the original array intact:
  If you don't want to modify the original array, create a copy first:

  $newArray = $originalArray;
  addLevelToNodes($newArray);
  

What This Does #

• Top-level nodes (like the ones with id:1 and id:2) get level:1.
• Direct children of those nodes (like id:101 and id:161) get level:2.
• Nested children (like id:300 under id:161) get level:3, and so on for deeper levels.
• The function automatically handles both numeric-indexed child arrays and named keys like children—any array containing nodes will be processed recursively.

Example Output #

After running the function, your array will look like this:

[
    [
        'id' => 1,
        'parentid' => null,
        'level' => 1,
        [
            'id' => 101,
            'parentid' => 1,
            'level' => 2
        ]
    ],
    [
        'id' => 2,
        'parentid' => null,
        'level' => 1,
        [
            'id' => 161,
            'parentid' => 2,
            'level' => 2,
            'children' => [
                [
                    'id' => 300,
                    'parentid' => 161,
                    'level' => 3
                ]
            ]
        ]
    ]
]

内容的提问来源于stack exchange，提问作者Nibboro