Php/docs/function.sort
sort
(PHP 4, PHP 5, PHP 7)
sort — Sort an array
Description
sort
( array &$array
[, int $flags
= SORT_REGULAR
] ) : bool
This function sorts an array. Elements will be arranged from lowest to highest when this function has completed.
Note:
If two members compare as equal, their relative order in the sorted array is undefined.
Parameters
array
The input array.
flags
The optional second parameter
flags
may be used to modify the sorting behavior using these values:Sorting type flags:
SORT_REGULAR
- compare items normally; the details are described in the comparison operators sectionSORT_NUMERIC
- compare items numericallySORT_STRING
- compare items as strings-
SORT_LOCALE_STRING
- compare items as strings, based on the current locale. It uses the locale, which can be changed using setlocale() -
SORT_NATURAL
- compare items as strings using "natural ordering" like natsort() -
SORT_FLAG_CASE
- can be combined (bitwise OR) withSORT_STRING
orSORT_NATURAL
to sort strings case-insensitively
Return Values
Returns TRUE
on success or FALSE
on failure.
Examples
Example #1 sort() example
<?php$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 functionassigns 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 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