ArrayObject::uasort

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

ArrayObject::uasort — Sort the entries with a user-defined comparison function and maintain key association

Descrizione

public ArrayObject::uasort(callable $callback): true

This function sorts the entries such that keys maintain their correlation with the entry that they are associated with, using a user-defined comparison function.

This is used mainly when sorting associative arrays where the actual element order is significant.

Nota:
If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.

Elenco dei parametri

callback: La funzione di confronto deve restituire un intero minore, uguale o maggiore di zero se il primo argomento è considerato essere minore, uguale o maggiore del secondo.

callback(mixed $a, mixed $b): int

Attenzione
Returning non-integer values from the comparison function, such as float, will result in an internal cast to int of the callback's return value. So values such as 0.99 and 0.1 will both be cast to an integer value of 0, which will compare such values as equal.

Valori restituiti

Always returns true.

Log delle modifiche

Versione	Descrizione
8.2.0	The return type is `true` now; previously, it was bool.

Esempi

Example #1 ArrayObject::uasort() example

<?php
// Comparison function
function cmp($a, $b) {
    if ($a == $b) {
        return 0;
    }
    return ($a < $b) ? -1 : 1;
}

// Array to be sorted
$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);
$arrayObject = new ArrayObject($array);
print_r($arrayObject);

// Sort and print the resulting array
$arrayObject->uasort('cmp');
print_r($arrayObject);
?>

Il precedente esempio visualizzerà:

Array
(
    [a] => 4
    [b] => 8
    [c] => -1
    [d] => -9
    [e] => 2
    [f] => 5
    [g] => 3
    [h] => -4
)
Array
(
    [d] => -9
    [h] => -4
    [c] => -1
    [e] => 2
    [g] => 3
    [a] => 4
    [f] => 5
    [b] => 8
)

Vedere anche:

ArrayObject::asort() - Sort the entries by value
ArrayObject::ksort() - Sort the entries by key
ArrayObject::natsort() - Sort entries using a "natural order" algorithm
ArrayObject::natcasesort() - Sort an array using a case insensitive "natural order" algorithm
ArrayObject::uksort() - Sort the entries by keys using a user-defined comparison function
uasort() - Ordina un array mediante una funzione definita dall'utente e mantiene le associazioni

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User Contributed Notes 1 note

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poxetinho at gmail dot com ¶

13 years ago


Note that return values between (-1, 1) are being considered as 0.

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