Sort an assoc array index into reverse order

Question

Hey guys I hope a very quick one!

I have an array

array(
(int) 30 => array(
    'score' => (int) 30,
    'max_score' => (int) 40,
    'username' => 'joeappleton',
    'user_id' => '1'
),
(int) 34 => array(
    'score' => (int) 34,
    'max_score' => (int) 40,
    'username' => 'joeappleton',
    'user_id' => '1'
),
(int) 36 => array(
    'score' => (int) 36,
    'max_score' => (int) 40,
    'username' => 'joeappleton',
    'user_id' => '1'
)

)

I need it to be sorted into descending order, by reference of the array key:

array( 
    36 => array('score' => 36, 'max_score' => 40, 'username' => 'joeappleton', 'user_id' => '1'),
    34 => array('score' => 34, 'max_score' => 40, 'username' => 'joeappleton', 'user_id' => '1'),
    30 => array('score' => 36, 'max_score' => 40, 'username' => 'joeappleton', 'user_id' => '1')
);

I've tried krsort() but no joy, it seems to return a bool. Any ideas?

Is there any reason you can't create the array in descending order? That is, do you need to use it in both orderings (ascending and descending) or only one? — vernonner3voltazim, Sep 11 '14 at 07:49
All the sorting functions modify the input array, they don't return a sorted array. — Barmar, Sep 11 '14 at 07:51

score 0 · Answer 1 · answered Sep 11 '14 at 08:00

0

Ok the issue was that krsort(), uses pass by reference. It sorts the original array and returns a bool.

I changed

return krsort($returnArray); //this returned true

to

krsort($returnArray); return $returnArray;

answered Sep 11 '14 at 08:00

Joe Appleton

31
3

score 0 · Answer 2 · answered Sep 11 '14 at 08:43

we can use array_multisort,which give the same result you want!!!

<?php 
$people = array( 
(int) 30 => array(
'score' => (int) 30,
'max_score' => (int) 40,
'username' => 'joeappleton',
'user_id' => '1'
),
(int) 34 => array(
'score' => (int) 34,
'max_score' => (int) 40,
'username' => 'joeappleton',
'user_id' => '1'
),
(int) 36 => array(
'score' => (int) 36,
'max_score' => (int) 40,
'username' => 'joeappleton',
'user_id' => '1'
)); 
//var_dump($people); 

$sortArray = array(); 

foreach($people as $person){ 
foreach($person as $key=>$value){ 
    if(!isset($sortArray[$key])){ 
        $sortArray[$key] = array(); 
    } 
    $sortArray[$key][] = $value; 
} 
} 

$orderby = "score"; //change this to whatever key you want from the array 

array_multisort($sortArray[$orderby],SORT_DESC,$people); 

//var_dump($people); 
print_r($people);
?>

Sort an assoc array index into reverse order

2 Answers2