(PHP 4 >= 4.0.1, PHP 5, PHP 7)
array_unique — Removes duplicate values from an array
array_unique ( array $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.
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 (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. Returns the filtered array.
| 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. |
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"
}
Note: Note that array_unique() is not intended to work on multi dimensional arrays.
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https://www.php.net/manual/en/function.array-unique.php