Why Does `array_diff_assoc()` Include Common Rows When Comparing 2D Arrays?

Filter 2D Array Rows Using Another Array

You have two 2D arrays, and intend to use array_diff_assoc() to identify the unique rows in the first array that are not present in the second. However, you encounter an issue where the common rows are included in the result.

The issue stems from the way array_diff_assoc() compares values. It performs a strict string comparison, meaning that values must be identical in both type and value to be considered equal. In the given example:

<code class="php">$array1 = [
    [12 => 'new q sets'],
    [11 => 'common set']
];

$array2 = [
    [11 => 'common set']
];</code>

When array_diff_assoc($array1, $array2) is called, the string representation of both arrays is "Array." Thus, the difference is detected based on the additional row in $array1 ([12] => 'new q sets'). As a result, the common row ([11] => 'common set') is included in the difference.

To resolve this issue, consider using a different comparison approach. If the data in the arrays is numeric or can be converted to numeric, you can use array_diff_uassoc(), which allows you to specify a custom comparison function. Alternatively, you can manually filter the rows by iterating over both arrays and checking for value equality.

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