Why is it necessary to assign the return value of array_reverse to a variable when reversing sub-arrays in PHP?

When reversing sub-arrays in PHP using `array_reverse`, it is necessary to assign the return value to a variable in order to actually store the reversed array. If the return value is not assigned to a variable, the original array will remain unchanged. By assigning the return value to a variable, you can then access and use the reversed sub-array as needed in your code.

// Original array
$originalArray = [1, 2, 3, 4, 5];

// Reversing a sub-array and assigning the return value to a variable
$reversedArray = array_reverse(array_slice($originalArray, 1, 3));

// Output the reversed sub-array
print_r($reversedArray);