arsort

(PHP 4, PHP 5, PHP 7, PHP 8)

arsort — Ordena un array en orden descendente y conserva la asociación de los índices

Descripción

arsort(array &$array, int $flags = SORT_REGULAR): true

Ordena array en el lugar en orden descendente, de tal manera que la correlación entre las claves y los valores se conserve.

El uso principal es cuando se ordenan arrays asociativos donde el orden de los elementos es importante.

Nota:
Si dos miembros se comparan como iguales, ellos mantendrán su orden original. Antes de PHP 8.0.0, su orden relativo en un array ordenado era indefinido.

Nota:
Reinicia el puntero interno del array al primer elemento.

Parámetros

array

El array de entrada.

flags

The optional second parameter flags may be used to modify the sorting behavior using these values:

Sorting type flags:

SORT_REGULAR - compare items normally; the details are described in the comparison operators section
SORT_NUMERIC - compare items numerically
SORT_STRING - compare items as strings
SORT_LOCALE_STRING - compare items as strings, based on the current locale. It uses the locale, which can be changed using setlocale()
SORT_NATURAL - compare items as strings using "natural ordering" like natsort()
SORT_FLAG_CASE - can be combined (bitwise OR) with SORT_STRING or SORT_NATURAL to sort strings case-insensitively

Valores devueltos

Siempre devuelve true.

Historial de cambios

Versión	Descripción
8.2.0	The return type is `true` now; previously, it was bool.

Ejemplos

Ejemplo #1 Ejemplo con arsort()

<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
arsort($fruits);
foreach ($fruits as $key => $val) {
    echo "$key = $val\n";
}
?>

El resultado del ejemplo sería:

a = orange
d = lemon
b = banana
c = apple

Las frutas han sido ordenadas en orden alfabético inverso, y sus índices respectivos han sido conservados.

Ver también

sort() - Ordena un array en orden creciente
asort() - Ordena un array en orden ascendente y conserva la asociación de los índices
comparación de funciones de orden de arrays

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User Contributed Notes 3 notes

down

morgan at anomalyinc dot com ¶

25 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

down

stephenakins at gmail dot com ¶

7 years ago

I have two servers; one running 5.6 and another that is running 7.  Using this function on the two servers gets me different results when all of the values are the same.  

<?php

$list = json_decode('{"706":2,"703":2,"702":2,"696":2,"658":2}', true);

print_r($list);

arsort($list);
echo "<br>";

print_r($list);

?>

PHP 5.6 results:
Array ( [706] => 2 [703] => 2 [702] => 2 [696] => 2 [658] => 2 ) 
Array ( [658] => 2 [696] => 2 [702] => 2 [703] => 2 [706] => 2 )

PHP 7 results:
Array ( [706] => 2 [703] => 2 [702] => 2 [696] => 2 [658] => 2 ) 
Array ( [706] => 2 [703] => 2 [702] => 2 [696] => 2 [658] => 2 )

down

-1

FatBat ¶

13 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.

?>

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