krsort

(PHP 4, PHP 5, PHP 7, PHP 8)

krsortSort an array by key in descending order

Description

krsort(array &$array, int $flags = SORT_REGULAR): true

Sorts array in place by keys in descending order.

Note:

If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.

Note:

Resets array's internal pointer to the first element.

Parameters

array

The input array.

flags

The optional second parameter flags may be used to modify the sorting behavior using these values:

Sorting type flags:

Return Values

Always returns true.

Changelog

Version Description
8.2.0 The return type is true now; previously, it was bool.

Examples

Example #1 krsort() example

<?php
$fruits
= array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
krsort($fruits);
foreach (
$fruits as $key => $val) {
echo
"$key = $val\n";
}
?>

The above example will output:

d = lemon
c = apple
b = banana
a = orange

See Also

add a note

User Contributed Notes 2 notes

up
-33
Anonymous
18 years ago
To create a natural reverse sorting by keys, use the following function:

<?php
function natkrsort($array)
{
$keys = array_keys($array);
natsort($keys);

foreach (
$keys as $k)
{
$new_array[$k] = $array[$k];
}

$new_array = array_reverse($new_array, true);

return
$new_array;
}
?>
up
-33
peter at pmkmedia dot com
20 years ago
Best deal sorting:

This is a function that will sort an array with integer keys (weight) and float values (cost) and delete 'bad deals' - entries that are more costly than other entries that have greater or equal weight.

Input: an array of unsorted weight/cost pairs
Output: none

function BEST_DEALS($myarray)
{ // most weight for least cost:
// ? Peter Kionga-Kamau, http://www.pmkmedia.com
// thanks to Nafeh for the reversal trick
// free for unrestricted use.
krsort($myarray, SORT_NUMERIC);
while(list($weight, $cost) = each($myarray))
{ // delete bad deals, retain best deals:
if(!$lastweight)
{
$lastweight=$weight;
$lastcost = $cost;
}
else if($cost >= $lastcost) unset($myarray[$weight]);
else
{
$lastweight=$weight;
$lastcost = $cost;
}
}
ksort($myarray);
}
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