Array Functions
PHP Manual

asort

Sort an array in ascending order and maintain index association

Description

true asort(array &$array, int $flags = SORT_REGULAR)

Sorts array in place in ascending order, such that its keys maintain their correlation with the values they are associated with.

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

Note:

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.

Note:

Resets array's internal pointer to the first element.

Parameters

array

The input array.

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

Return Values

Always returns true.

Changelog

Version Description
8.2.0 The return type is true now; previously, it was bool.

Examples

Example #1 asort example

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

The above example will output:

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

The fruits have been sorted in alphabetical order, and the index associated with each element has been maintained.

See Also