PHP | Different characters in the given string

We have string str and we need to find the string with all unique characters from the given string. All different characters should be printed in ascending order.

Examples:

Input : $str = "GeeksforGeeks"
Output : Gefkors
Explanation, the unique characters in the given
string $str in ascending order are G, e, f, k, 
o, r and s

Input : $str = "Computer Science Portal"
Output : CPSaceilmnoprtu
Explanation, the unique characters in the given 
string $str are C, P, S, a, c, ei, l, m, n, o, 
p, r, t and u

The problem can be solved using PHP in built function for collecting all the unique characters used in the given string.The in built function used for the given problem is:

1. count_chars():The in built function has parameter which contains return mode an integer type which are as such 0, 1, 2, 3, 4 in which return mode 3 returns the string of all different characters used in the given string in ascending order.

Note: The string is case-sensitive.

Example 1:

<?php
// PHP code to find string containing unique
// characters in the given string

$str = "Geeksforgeeks";
$result = (count_chars($str, 3));

echo ($result);
?>

Output:

Gefgkors

Example 2:

<?php
// PHP code to find string containing unique
// characters  in the given string

$str = "GeeksforGeeks";
$result = (count_chars($str, 3));

echo ($result);
?>

Output:

Gefkors

Example3:

<?php
// PHP code to find string containing unique
// characters in the given string

$str = "Computer Science Portal";
$result = (count_chars($str, 3));

echo ($result);
?>

Output:

CPSaceilmnoprtu