PHP krsort() Function

Last Updated : 11 Jul, 2025
The krsort() function is an inbuilt function in PHP which is used to sort an array by key in reverse order according to its index values. It sorts in a way that relation between indices and values is maintained. Syntax:
bool krsort( $array, $sorting_type )
Parameters: This function accepts two parameters as mentioned above and described below:
  • $array: This parameter specifies the array which to be sort. It is a mandatory parameter.
  • $sorting_type: This is an optional parameter. There are different sorting types which are discussed below:
    • SORT_REGULAR: The value of $sorting_type is SORT_REGULAR then items are compare normally.
    • SORT_NUMERIC: The value of $sorting_type is SORT_NUMERIC then items are compares numerically.
    • SORT_STRING: The value of $sorting_type is SORT_STRING then items are compares as string.
    • SORT_LOCALE_STRING: The value of $sorting_type is SORT_STRING then items are compares as string, based on current locale.
Return Value: This function returns True on success or False on failure. Below programs illustrate the krsort() function in PHP. Program 1: php
<?php
// PHP program to illustrate
// krsort()function

// Input different array elements
$arr = array("0" =>"Technology",
             "1" =>"Machine",
             "2" =>"GeeksforGeeks",
             "3" =>"Graphics",
             "4" =>"Videos",
             "5" =>"Report",
             "6" =>"Article",
             "7" =>"Placement",
             "8" =>"Contribute",
             "9" =>"Reset",
             "10" =>"Copy",
        );

// Implementation of krsort()
krsort($arr);

// for-Loop for displaying result
foreach ($arr as $key => $val) {
    echo "[$key] = $val";
    echo"\n";
}

?>
Output:
[10] = Copy
[9] = Reset
[8] = Contribute
[7] = Placement
[6] = Article
[5] = Report
[4] = Videos
[3] = Graphics
[2] = GeeksforGeeks
[1] = Machine
[0] = Technology
Program 2: php
<?php
// PHP program to illustrate
// krsort function
    
// Input different array elements
$arr = array("a" => 11,
             "b" => 22,
             "d" => 33,
             "n" => 44,
             "o" => 55,
             "p" => 66,
             "r" => 77,
             "s" => 2,
             "q" => -11,
             "t" => 3,
             "u" => 1000,
             "z" => 1,                            
        );
// Implementation of krsort
krsort($arr);

// for-Loop for displaying result
foreach ($arr as $key => $val) {
    echo "[$key] = $val";
    echo"\n";
}

?>
Output:
[z] = 1
[u] = 1000
[t] = 3
[s] = 2
[r] = 77
[q] = -11
[p] = 66
[o] = 55
[n] = 44
[d] = 33
[b] = 22
[a] = 11
Related Articles: Reference: https://www.php.net/manual/en/function.krsort.php
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