PHP Manual: Sort an array

Description

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

This function sorts an array. Elements will be arranged from lowest to highest when this function has completed.

Note:
If two members compare as equal, their relative order in the sorted array is undefined.

Parameters

array

The input array.

sort_flags

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

Sorting type flags:

SORT_REGULAR - compare items normally (don't change types)
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

Returns TRUE on success or FALSE on failure.

Changelog

Version	Description
5.4.0	Added support for `SORT_NATURAL` and `SORT_FLAG_CASE` as `sort_flags`
5.0.2	Added `SORT_LOCALE_STRING`

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: 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: 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 unpredictable results.

sort