Reverse PHP array to form new array

There are two ways to reverse a PHP array: use the built-in function array_reverse() to reverse the array; use a loop to manually reverse the order of the array elements.

How to reverse a PHP array

Reversing an array is the process of reversing the order of the elements in the array. There are several ways to achieve array reversal in PHP.

Use the built-in function array_reverse()

array_reverse() function is the simplest way to reverse an array. It accepts an array as argument and returns a new reversed array:

<?php
$arr = [1, 2, 3, 4, 5];
$reversedArr = array_reverse($arr);

print_r($reversedArr);
?>

Output:

Array ( [4] => 5 [3] => 4 [2] => 3 [1] => 2 [0] => 1 )

Use a loop

if you need For more inversion of control processes, you can use loops:

<?php
$arr = [1, 2, 3, 4, 5];
$reversedArr = [];

for ($i = count($arr) - 1; $i >= 0; $i--) {
  $reversedArr[] = $arr[$i];
}

print_r($reversedArr);
?>

Output:

Array ( [0] => 5 [1] => 4 [2] => 3 [3] => 2 [4] => 1 )

Practical case

Suppose you have the following array, representing user input A list of integer arrays:

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

To reverse this array and print the elements in a specific order, you can use the following code:

<?php
$arr = [1, 3, 2, 5, 4];
$reversedArr = array_reverse($arr);

foreach ($reversedArr as $num) {
  echo "元素: $num\n";
}
?>

Output:

元素: 4
元素: 5
元素: 2
元素: 3
元素: 1

The above is the detailed content of Reverse PHP array to form new array. For more information, please follow other related articles on the PHP Chinese website!