# sort

(PHP 4, PHP 5, PHP 7)

sort — Sort an array

### Description

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

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; 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

Returns `TRUE` on success or `FALSE` on failure.

### 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 unexpected results, if `sort_flags` is `SORT_REGULAR`,

### See Also

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