How to remove duplicate values from a multi-dimensional array in PHP

To remove duplicate values from a multi-dimensional array in PHP, you can use the following approach:

1. Flatten the multi-dimensional array into a single-dimensional array using the array_merge() function.
2. Remove duplicate scalar values using the array_unique() function.
3. Reshape the array back into a multi-dimensional structure using the array_chunk() function. Note: This method assumes all original sub-arrays had identical lengths. If the deduplicated count is not divisible by that length, the final sub-array will be shorter.

Here is an example of how you can implement this:

How to remove duplicate values from a multi-dimensional array in PHP?

<?php

$input = [[1, 2, 3], [2, 3, 4], [3, 4, 5]];

// Flatten the multi-dimensional array into a single-dimensional array
$single_dimensional_array = array_merge(...$input);

// Remove duplicate scalar values
$single_dimensional_array = array_unique($single_dimensional_array);

// Reshape back into a multi-dimensional array
// Note: Assumes fixed sub-array lengths. The last chunk may be shorter if the count isn't divisible.
$result = array_chunk($single_dimensional_array, count($input[0]));

print_r($result);

The resulting array $result will contain the values of the original array $input with duplicate values removed, reshaped to match the original sub-array length.