sizeof
uasort
Array Functions
PHP Manual

# sort

(PHP 4, PHP 5)

sort — 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.

### 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.

### See Also

- asort() - Sort an array and maintain index association
- The comparison of array sorting functions

sizeof
uasort
Array Functions
PHP Manual