key
Function • Params and return types changed in PHP 8.0
Fetch a key from an array.
key Function synopsis
key(object|array $array): string|int|nullParameters
$array
Typeobject|array
The array.
Return value
Typestring|int|null
The key function simply returns the
key of the array element that's currently being pointed to by the
internal pointer. It does not move the pointer in any way. If the
internal pointer points beyond the end of the elements list or the array is
empty, key returns null.
Changes to the key Function
PHP 8.0
- Return type added:
string|int|null - Parameter name of parameter #1 changed:
$argto$array - Parameter type added for parameter #1 (
$array):object|array
- key($arg)
+ key(object|array $array): string|int|nullkey Function Availability
key Function Availability| PHP Version | Availability |
|---|---|
| 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 |