API GetNumFriends

Returns how many friends you have. numberOfFriends, onlineFriends = GetNumFriends

Returns

 * numberOfFriends : Integer - The number of friends you have (i.e. the highest valid friend index you can use to get friend information).
 * onlineFriends : Integer - The number of online friends.

Example
DEFAULT_CHAT_FRAME:AddMessage("I've got " .. (GetNumFriends) .. " friend(s)");

Result
Displays the number of friends you currently have in the default chat frame.