array_reverse()

(PHP 4, PHP 5, PHP 7)

返回单元顺序相反的数组

说明

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

array_reverse()接受数组$array作为输入并返回一个单元为相反顺序的新数组。

参数

$array: 输入的数组。
$preserve_keys: 如果设置为TRUE会保留数字的键。非数字的键则不受这个设置的影响，总是会被保留。

返回值

返回反转后的数组。

范例

Example #1array_reverse()例子

<?php
$input  = array("php", 4.0, array("green", "red"));
$reversed = array_reverse($input);
$preserved = array_reverse($input, true);
print_r($input);
print_r($reversed);
print_r($preserved);
?>

以上例程会输出：

Array
(
    [0] => php
    [1] => 4
    [2] => Array
        (
            [0] => green
            [1] => red
        )
)
Array
(
    [0] => Array
        (
            [0] => green
            [1] => red
        )
    [1] => 4
    [2] => php
)
Array
(
    [2] => Array
        (
            [0] => green
            [1] => red
        )
    [1] => 4
    [0] => php
)

参见

array_flip() 交换数组中的键和值

Needed to just reverse keys. Don't flog me if there is a better way. This was a simple solution.
<?php
function array_reverse_keys($ar){
  return array_reverse(array_reverse($ar,true),false);
}
?>

Here are a couple of routines to swap the order of two elements in an array
<?php
function array_swap_forward($arr,$elem)
{
$ndx = array_search($elem,$arr) - 1;
$b4 = array_slice($arr,0,$ndx);
$mid = array_reverse(array_slice($arr,$ndx,2));
$after = array_slice($arr,$ndx + 2);
return array_merge($b4,$mid,$after);
}
function array_swap_back($arr,$elem)
{
$ndx = array_search($elem,$arr);
$b4 = array_slice($arr,0,$ndx);
$mid = array_reverse(array_slice($arr,$ndx,2));
$after = array_slice($arr,$ndx + 2);
return array_merge($b4,$mid,$after);
}
$arr =array('a','b','c','d','e','f');
print_r(array_swap_forward($arr,'c'));
echo '<br>';
print_r(array_swap_back($arr,'c'));
?>

This code can help in recursive reversing of the array...
<?php
$arr1 = array(2,1,array(5,2,1,array(9,8,7)),5,0);
$arr1 = array_reverse($arr1);
function Reverse_Array($array)
{  $index = 0;
  foreach ($array as $subarray)
  {  if (is_array($subarray))
    {  $subarray = array_reverse($subarray);
      $arr = Reverse_Array($subarray);
      $array[$index] = $arr;
    }
    else {$array[$index] = $subarray;}
    $index++;
  }
  return $array;
}
$arr2 = Reverse_Array($arr1);
?>