php array_reverse returns an array in reverse order detailed explanation

This article mainly introduces the code of php array_reverse to return array instances in reverse order. It has certain reference value. Those who are interested can learn about it.

php The array_reverse function returns an array with the units in reverse order. This function has two parameters. The first parameter indicates the array to be processed. The second parameter is optional and specifies whether to retain the key names of the original array. This article explains how to use the array_reverse function through examples. Coders who need it can refer to it.

Basic syntax of the array_reverse function:

array array_reverse ( array $array [, bool $preserve_keys = false ] )

array_reverse() accepts an array array as input and returns an A new array with the cells in reverse order.

If the second parameter is specified as true, the key name of the element remains unchanged, otherwise the key name will be lost.

Parameter introduction

##ParameterDescriptionarrayRequired. The input array. preserve

	Optional. Specifies whether to retain the original array key names. Returns an array with cells in reverse order. If set to TRUE numeric keys will be retained. Non-numeric keys are not affected by this setting and will always be retained. Possible values: true false

Return value

Returns the reversed array.

Example:

<?php
$input = array("php", 4.0, array("green", "red"));
$result = array_reverse($input);
$result_keyed = array_reverse($input, true);
?>

This will make $result and $result_keyed have the same unit, but note the key name difference. The printouts of $result and $result_keyed are respectively:

Array
(
 [0] => Array
 (
  [0] => green
  [1] => red
 )

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

 [1] => 4
 [0] => php
)

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