PHP 5.4.36 Released

arsort

(PHP 4, PHP 5)

arsort Sortiert ein Array in umgekehrter Reihenfolge und erhält die Index-Assoziation

Beschreibung

bool arsort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

Diese Funktion sortiert ein Array so, dass der Zusammenhang zwischen den Indizes und den entsprechenden Elementen des Arrays erhalten bleibt.

Dies wird hauptsächlich zur Sortierung assoziativer Arrays verwendet, bei denen die aktuelle Reihenfolge der Elemente bedeutend ist.

Parameter-Liste

array

Das Eingabe-Array.

sort_flags

Sie können das Verhalten der Sortierung mittels dem optionalen Parameter sort_flags beeinflussen, für Details siehe sort().

Rückgabewerte

Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.

Beispiele

Beispiel #1 arsort()-Beispiel

<?php
$fruits 
= array("d" => "Zitrone""a" => "Orange""b" => "Banane""c" => "Apfel");
arsort($fruits);
foreach (
$fruits as $key => $val) {
    echo 
"$key = $val\n";
}
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

d = Zitrone
a = Orange
b = Banane
c = Apfel

Die Früchte wurden in umgekehrter alphabetischer Reihenfolge sortiert und die Zuordnung zwischen Index und Element blieb erhalten.

Siehe auch

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User Contributed Notes 5 notes

up
4
morgan at anomalyinc dot com
15 years ago
If you need to sort a multi-demension array, for example, an array such as

$TeamInfo[$TeamID]["WinRecord"]
$TeamInfo[$TeamID]["LossRecord"]
$TeamInfo[$TeamID]["TieRecord"]
$TeamInfo[$TeamID]["GoalDiff"]
$TeamInfo[$TeamID]["TeamPoints"]

and you have say, 100 teams here, and want to sort by "TeamPoints":

first, create your multi-dimensional array. Now, create another, single dimension array populated with the scores from the first array, and with indexes of corresponding team_id... ie
$foo[25] = 14
$foo[47] = 42
or whatever.
Now, asort or arsort the second array.
Since the array is now sorted by score or wins/losses or whatever you put in it, the indices are all hoopajooped.
If you just walk through the array, grabbing the index of each entry, (look at the asort example. that for loop does just that) then the index you get will point right back to one of the values of the multi-dimensional array.
Not sure if that's clear, but mail me if it isn't...
-mo
up
0
FatBat
3 years ago
Needed to get the index of the max/highest value in an assoc array.
max() only returned the value, no index, so I did this instead.

<?php
reset
($x);   // optional.
arsort($x);
$key_of_max = key($x);   // returns the index.
?>
up
0
rodders_plonker at yahoo dot com
14 years ago
I was having trouble with the arsort() function on an older version of PHP which was returning an error along the lines of 'wrong perameter count for function arsort' when I tried to use a flag for numeric sorting (2/SORT_NUMERIC).
I figured, as I only wanted to sort integers, I could pad numbers from the left to a specific length with 0's (using the lpad function provided by improv@magma.ca in the notes at http://www.php.net/manual/ref.strings.php).
A string sort then correctly sorts numerically (i.e. {30,2,10,21} becomes {030,021,010,002} not {30,21,2,10}) when echoing the number an (int)$string_name hides the leading 0's.

Made my day :).

Rodders.
up
-3
jordancdarwin at googlemail dot com
7 years ago
A lot of people seem to trip up on this and ask me questions as to debugging. Bear in mind that this returns boolean, and does not return an array of affected items.

$array = array("One"=>1, "Three" => 3,"Two" =>2);
print_r(asort($array));

If successful, will return 1, and error if there is a string used. Useful to note so then people stop asking me :D
up
-4
sebas2day
2 years ago
If you are dealing with a multidimensional array you want to sort, then this might be helpfull:

<?php
function array_sort($arr){
    if(empty(
$arr)) return $arr;
    foreach(
$arr as $k => $a){
        if(!
is_array($a)){
           
arsort($arr); // could be any kind of sort
           
return $arr;
        }else{
           
$arr[$k] = array_sort($a);
        }
    }
    return
$arr;
}
?>
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