What is tht arsort() function in php ?

The arsort() function sorts an associative array in descending order, as reported by the value.

why use arsort() function in php ?

arsort() is fundamentally used when sorting associative array in descending order, according to the value..

You can see below example of arsort() function in php.

<?php

$Getage=array("Joe"=>"28","Anthony"=>"35","Tori"=>"45");

//now call the asort() function for sorting associative array 
arsort($Getage);

////loop rstart for find all value
foreach($Getage as $key=>$value)
    {
    echo "Name=" . $key . ", Age=" . $value;
    echo "<br>";
    }
?>

Output will come

Name=Tori, Age=45

Name=Anthony, Age=35

Name=Joe, Age=28