sort

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

sort — Sort an array in ascending order

Description

sort(array &$array, int $flags = SORT_REGULAR): bool

Sorts array in place by values in ascending order.

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: This function assigns new keys to the elements in array. It will remove any existing keys that may have been assigned, rather than just reordering the keys.

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.

Examples

Example #1 sort() example


<?php

$fruits = array("lemon", "orange", "banana", "apple");
sort($fruits);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}

?>

The above example will output:

fruits[0] = apple
fruits[1] = banana
fruits[2] = lemon
fruits[3] = orange

The fruits have been sorted in alphabetical order.

Example #2 sort() example using case-insensitive natural ordering


<?php

$fruits = array(
    "Orange1", "orange2", "Orange3", "orange20"
);
sort($fruits, SORT_NATURAL | SORT_FLAG_CASE);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}

?>

The above example will output:

fruits[0] = Orange1
fruits[1] = orange2
fruits[2] = Orange3
fruits[3] = orange20

The fruits have been sorted like natcasesort().

Notes

Note: Like most PHP sorting functions, sort() uses an implementation of » Quicksort. The pivot is chosen in the middle of the partition resulting in an optimal time for already sorted arrays. This is however an implementation detail you shouldn't rely on.

Warning

Be careful when sorting arrays with mixed types values because sort() can produce unexpected results, if flags is SORT_REGULAR.