How to Re-index Subarray Elements in Multidimensional Arrays?

Re-indexing Subarray Elements in Multidimensional Arrays

In multidimensional arrays, resetting key indices can be useful for maintaining a predictable order or aligning values with other arrays.

Problem:

How do you reset the keys of subarrays within a multidimensional array, renumbering them sequentially from zero? Consider the following example:

<code class="php">$arr = [
    '1_Name' => [
        1 => 'leo',
        4 => null
    ],
    '1_Phone' => [
        1 => 12345,
        4 => 434324
    ]
];
// Expected output:
// Array (
//     [1_Name] => [
//         0 => 'leo',
//         1 => null
//     ]
//     [1_Phone] => [
//         0 => 12345,
//         1 => 434324
//     ]
// )</code>

Solution:

To achieve this, you can use the following approach:

<code class="php">$arr = array_map('array_values', $arr);</code>

The array_map() function applies the array_values() function to each subarray within $arr. array_values() re-indexes the subarray's keys sequentially from zero.

<code class="php">// array_values() for first-level arrays only
$arr = array_values($arr);</code>

For first-level array key resetting, you can use array_values() without array_map().

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