table.Count
Example
There are 4 keys in this table. So it will output "4"
Output: 
Example
Difference between the length (#) operator and this function.
The length (#) operator is generally considered faster, but has limitations.
Output: 
 Garry's Mod
			Garry's Mod 
		 Rust
			Rust 
		 Steamworks
			Steamworks 
		 Wiki Help
			Wiki Help