What is the difference between array_diff() and array_diff_assoc() in PHP, and when should each be used?

The main difference between array_diff() and array_diff_assoc() in PHP is how they compare the elements of arrays. array_diff() compares the values of the arrays and returns the difference, while array_diff_assoc() compares both the keys and the values of the arrays. array_diff() should be used when only the values need to be compared, while array_diff_assoc() should be used when both keys and values need to be compared.

// Using array_diff() to compare values only
$array1 = [1, 2, 3, 4, 5];
$array2 = [3, 4, 5, 6, 7];
$diff = array_diff($array1, $array2);
print_r($diff); // Output: [1, 2]

// Using array_diff_assoc() to compare keys and values
$array1 = ['a' => 1, 'b' => 2, 'c' => 3];
$array2 = ['a' => 1, 'b' => 4, 'c' => 5];
$diff = array_diff_assoc($array1, $array2);
print_r($diff); // Output: ['b' => 2, 'c' => 3]