array_key_exists

Function • Params and return types changed in PHP 8.0

Checks if the given key or index exists in the 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_key_exists Function synopsis

array_key_exists($key, array $array): bool

Parameters

$key

Value to check.

$array

Typearray

An array with keys to check.

Return value

Typebool

Returns true on success, false on failure

[`array_key_exists`](/codex/array_key_exists) will search for the keys in the first dimension only.
Nested keys in multidimensional arrays will not be found.

Changes to the array_key_exists Function

PHP 8.0

  • Return type added: bool
  • Parameter name of parameter #2 changed: $search to $array
  • Parameter type added for parameter #2 ($array): array
- array_key_exists($key, $search)
+ array_key_exists($key, array $array): bool

array_key_exists 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