PHP:
int strpos ( string $haystack , mixed $needle [, int $offset= 0 ] )
string stristr ( string $haystack , mixed $needle [, bool $before_needle = false ] )
bool in_array ( mixed $needle , array $haystack [, bool $strict ] )
mixed array_search ( mixed $needle , array $haystack [, bool $strict ] )
Come on, decide on whether it's needle or haystack first!