Using PHP's array_reverse() Function to Reverse Arrays

PHP provides many useful functions, one of which is array_reverse() that reverses the order of elements in an array.

The syntax is

array_reverse ( array $array [, bool $preserve_keys = FALSE ] ) : array

where the optional $preserve_keys parameter determines whether original keys are kept.

Example 1 shows reversing an indexed array:

$fruits = array("apple", "banana", "cherry", "date");
$reversed_fruits = array_reverse($fruits);
print_r($reversed_fruits);

The output is:

Array<br/>(<br/>    [0] => date<br/>    [1] => cherry<br/>    [2] => banana<br/>    [3] => apple<br/>)

Example 2 demonstrates reversing an associative array while preserving keys:

$colors = array(
    "red" => "#FF0000",
    "green" => "#00FF00",
    "blue" => "#0000FF"
);
$reversed_colors = array_reverse($colors, true);
print_r($reversed_colors);

Result:

Array<br/>(<br/>    [blue] => #0000FF<br/>    [green] => #00FF00<br/>    [red] => #FF0000<br/>)

Example 3 combines array_reverse() with sort() to reverse and then sort an indexed array.

$numbers = array(3, 1, 4, 1, 5, 9, 2);
$reversed_sorted_numbers = array_reverse($numbers);
sort($reversed_sorted_numbers);
print_r($reversed_sorted_numbers);

The final sorted array is:

Array<br/>(<br/>    [0] => 1<br/>    [1] => 1<br/>    [2] => 2<br/>    [3] => 3<br/>    [4] => 4<br/>    [5] => 5<br/>    [6] => 9<br/>)

In summary, array_reverse() is a simple yet powerful PHP function for reversing arrays, with an optional parameter to preserve keys, and it can be combined with other array functions such as sort() for more complex operations.