array_key_exists

(PHP 4 >= 4.1.0)

array_key_exists -- Checks if the given key or index exists in the array

Description

bool array_key_exists ( mixed key, array search)

array_key_exists() returns TRUE if the given key is set in the array. key can be any value possible for an array index.

Note: This name of this function is key_exists() in PHP version 4.0.6.

See also isset().