PHP: array_unique() function
PHP: Removes duplicate values from an array
The array_unique() is used to remove duplicate values from an array.
Note: The keys are preserved. array_unique() sorts the values treated as a string at first, then will keep the first key encountered for every value, and ignore all following keys. It does not mean that the key of the first related value from the unsorted array will be kept.
Version:
(PHP 4 and above)
Syntax:
array_unique(array1, sort_flags)
Parameters:
| Name | Description | Required / Optional |
Type |
|---|---|---|---|
| array1 | The input array. | Required | Array |
| sort_flags | sort_flags is used to modify the sorting behavior using following values: SORT_REGULAR - compare items normally. SORT_NUMERIC - compare items numerically SORT_STRING - compare items as strings SORT_LOCALE_STRING - compare items as strings, based on the current locale |
Optional | Integer |
Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used.
Return value
The filtered array.
Value Type: Array
Example:
<?php
$fruits_list = array('Orange', 'Apple', ' Banana', 'Cherry', ' Banana');
$result = array_unique($fruits_list);
print_r($result);
?>
Output:
Array ( [0] => Orange [1] => Apple [2] => Banana [3] => Cherry )
Pictorial Presentation:
View the example in the browser
Practice here online :
See also
Previous: array_sum
Next: array_unshift
PHP: Tips of the Day
Constants can be defined inside classes using a const keyword.
Example:
class Foo {
const BAR_TYPE = "bar";
// reference from inside the class using self::
public function myMethod() {
return self::BAR_TYPE;
}
}
// reference from outside the class using <ClassName>::
echo Foo::BAR_TYPE;
Output:
bar
This is useful to store types of items.
<?php
class Logger {
const LEVEL_INFO = 1;
const LEVEL_WARNING = 2;
const LEVEL_ERROR = 3;
// we can even assign the constant as a default value
public function log($message, $level = self::LEVEL_INFO) {
echo "Message level " . $level . ": " . $message;
}
}
$logger = new Logger();
$logger->log("Info"); // Using default value
$logger->log("Warning", $logger::LEVEL_WARNING); // Using var
$logger->log("Error", Logger::LEVEL_ERROR); // using class
Output:
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