array_unique

Function • Params and return types changed in PHP 8.0

Removes duplicate values from an array.

PHP 5
PHP 7
PHP 8.0
Improved
PHP 8.1
PHP 8.2-8.3
PHP 8.4
PHP 8.5
PHP 8.6

array_unique Function synopsis

array_unique(array $array, int $flags = SORT_STRING): array

Parameters

$array

Typearray

The input array.

$flags

OptionalTypeintDefault valueSORT_STRING

The optional second parameter $flags may be used to modify the comparison behavior using these values:

$flags accepts one of the following constant values:

Return value

Typearray

Returns the filtered array.

Changes to the array_unique Function

PHP 8.0

  • Return type added: array
  • Parameter name of parameter #1 changed: $arg to $array
  • Parameter type added for parameter #1 ($array): array
  • Parameter type added for parameter #2 ($flags): int
  • Parameter default value added for position #2 ($flags): SORT_STRING
- array_unique($arg, $flags)
+ array_unique(array $array, int $flags = SORT_STRING): array

PHP 5.6

  • Optional parameter added - #2: $flags
- array_unique($arg)
+ array_unique($arg, $flags)

array_unique Function Availability

PHP VersionAvailability
PHP 8.6Upcoming Release Yes
PHP 8.5Supported (Latest) Yes
PHP 8.4Supported Yes
PHP 8.3Security-Fixes Only Yes
PHP 8.2Security-Fixes Only Yes
PHP 8.1Unsupported Yes
PHP 8.0Unsupported Yes
PHP 7.4Unsupported Yes
PHP 7.3Unsupported Yes
PHP 7.2Unsupported Yes
PHP 7.1Unsupported Yes
PHP 7.0Unsupported Yes
PHP 5.6Unsupported Yes
PHP 5.5Unsupported Yes
PHP 5.4Unsupported Yes
PHP 5.3Unsupported Yes