PHP | rsort() Function

The rsort() is an inbuilt function in PHP and is used to sort the array in descending order i.e, greatest to smallest. It sorts the actual array and hence changes are reflected in the array itself. The function provides us with 6 sorting types, according to which the array can be sorted.

Syntax:

rsort($array, sorting_type)

Parameters:



  1. $array: This parameter specifies the array which we want ot sort.
  2. sorting_type: This is an optional parameter. This parameter specifies the mode in which the sort operation will be performed on the input array. There are 6 sorting types which are described below:
    • SORT_REGULAR – When we pass 0 or SORT_REGULAR in the sorting_type parameter, the items in the array are compared normally
    • SORT_NUMERIC – When we pass 1 or SORT_NUMERIC in the sorting_type parameter, the items in the array are compared numerically
    • SORT_STRING – When we pass 2 or SORT_STRING in the sorting_type parameter, the items in the array are compared string-wise
    • SORT_LOCALE_STRING – When we pass 3 or SORT_LOCALE_STRING in the sorting_type parameter, the items in the array are compared as string based on current locale
    • SORT_NATURAL – When we pass 4 or SORT_NATURAL in the sorting_type parameter, the items in the array are compared as string using natural ordering
    • SORT_FLAG_CASE – When we pass 5 or SORT_FLAG_CASE in the sorting_type parameter, the items in the array are compared as strings. The items are treated as case-insensitive and then compared. It can be used using | (bitwise operator) with SORT_NATURAL or SORT_STRING.

Return Value: It returns a boolean value, TRUE on success and False in failure. It sorts the original array in descending which is passed as a parameter to it.

Examples:

Input : $array = [3, 4, 1, 2] 
Output : 
Array
(
    [0] => 4
    [1] => 3
    [2] => 2
    [3] => 1
)


Input : $array = ["geeks2", "raj1", "striver3", "coding4"]
Output :
Array
(
    [0] => striver3 
    [1] => raj1 
    [2] => geeks2 
    [3] => coding4
)

Below programs illsutrate the rsort() function in PHP:

Program 1: Program to demonstrate the use of rsort() function in descending order.

filter_none

edit
close

play_arrow

link
brightness_4
code

<?php
// PHP program to demonstrate the use of rsort() function
  
$array = array(3, 4, 2, 1);
  
// sorting fucntion used 
rsort($array); 
  
//prints the sorted array 
print_r($array);
?>

chevron_right


Output:

Array
(
    [0] => 4
    [1] => 3
    [2] => 2
    [3] => 1
)

Program 2: Program to demonstrate the use of rsort() function to sort the string case-sensitively in descending order.

filter_none

edit
close

play_arrow

link
brightness_4
code

<?php
// PHP program to demonstrate the use of rsort() function
// sorts the string case-sensitively 
$array = array("geeks", "Raj", "striver", "coding", "RAj");
  
// sorting fucntion used, sorts the string case-sensitively 
rsort($array, SORT_STRING); 
  
// prints the sorted array 
print_r($array);
?>

chevron_right


Output:

Array
(
    [0] => striver
    [1] => Raj
    [2] => RAj
    [3] => geeks
    [4] => coding
)

Program 3 : Program to demonstrate the use of rsort() function to sort the string case-insensitively in descending order.

filter_none

edit
close

play_arrow

link
brightness_4
code

<?php
// PHP program to demonstrate the use of sort() function
// sorts the string case-insensitively 
$array = array("geeks", "Raj", "striver", "coding", "RAj");
  
// sorting fucntion used, sorts the
// string case-insensitively 
rsort($array, SORT_STRING | SORT_FLAG_CASE); 
  
// prints the sorted array 
print_r($array);
?>

chevron_right


Output:

Array
(
    [0] => striver
    [1] => Raj
    [2] => RAj
    [3] => geeks
    [4] => coding
)

Reference:
http://php.net/manual/en/function.rsort.php



My Personal Notes arrow_drop_up

Striver(underscore)79 at Codechef and codeforces D

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.