(PHP 4, PHP 5, PHP 7, PHP 8)
krsort — Sort an array by key in descending order
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.
arrayThe input array.
flags
The optional second parameter flags
may be used to modify the sorting behavior using these values:
Sorting type flags:
SORT_REGULAR - compare items normally;
the details are described in the comparison operators section
SORT_NUMERIC - compare items numerically
SORT_STRING - compare items as strings
SORT_LOCALE_STRING - compare items as
strings, based on the current locale. It uses the locale,
which can be changed using setlocale()
SORT_NATURAL - compare items as strings
using "natural ordering" like natsort()
SORT_FLAG_CASE - can be combined
(bitwise OR) with
SORT_STRING or
SORT_NATURAL to sort strings case-insensitively
Always returns true.
Example #1 krsort() example
<?php
$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
krsort($fruits);
foreach ($fruits as $key => $val) {
echo "$key = $val\n";
}
?>The above example will output:
d = lemon c = apple b = banana a = orange
To create a natural reverse sorting by keys, use the following function:
<?php
function natkrsort($array)
{
$keys = array_keys($array);
natsort($keys);
foreach ($keys as $k)
{
$new_array[$k] = $array[$k];
}
$new_array = array_reverse($new_array, true);
return $new_array;
}
?>Best deal sorting:
This is a function that will sort an array with integer keys (weight) and float values (cost) and delete 'bad deals' - entries that are more costly than other entries that have greater or equal weight.
Input: an array of unsorted weight/cost pairs
Output: none
function BEST_DEALS($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);
}