array_unique
(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
array_unique — Removes duplicate values from an array
Description
$array, int $flags = SORT_STRING): array
Takes an input array and returns a new array
without duplicate values.
Note that keys are preserved. If multiple elements compare equal under
the given flags, then the key and value of
the first equal element will be retained.
Note: Two elements are considered equal if and only if
(string) $elem1 === (string) $elem2i.e. when the string representation is the same, the first element will be used.
Parameters
-
array -
The input array.
-
flags -
The optional second parameter
flagsmay 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.
-
Return Values
Returns the filtered array.
Changelog
| Version | Description |
|---|---|
| 7.2.0 |
If flags is SORT_STRING,
formerly array has been copied and non-unique
elements have been removed (without packing the array afterwards), but
now a new array is built by adding the unique elements. This can result
in different numeric indexes.
|
Examples
Example #1 array_unique() example
<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input);
print_r($result);
?>
The above example will output:
Array
(
[a] => green
[0] => red
[1] => blue
)
Example #2 array_unique() and types
<?php
$input = array(4, "4", "3", 4, 3, "3");
$result = array_unique($input);
var_dump($result);
?>
The above example will output:
array(2) {
[0] => int(4)
[2] => string(1) "3"
}
Notes
Note: Note that array_unique() is not intended to work on multi dimensional arrays.
