IEx has a really handy helper function available to us: i. This function comes in two separate arities, i/0 and i/1 (arities, in this case, being the number of arguments that we have to supply to each version of the function). i/0 displays information about the last value output in IEx, whereas i/1 displays information about a particular value or variable. Let's take a look at a few examples:

iex(3)> x = 5
5
iex(4)> i
Term
5
Data type
Integer
Reference modules
Integer
Implemented protocols
IEx.Info, Inspect, List.Chars, String.Chars

Let's talk about what the preceding example is giving us. First, it tells us the Term, which almost literally means the value itself. Next, we have the Data type, which tells us what Elixir is classifying this particular value as (in the example, it's an integer). Next, it tells us the Reference modules, which is a fancy way of telling us what modules we should use to be able to interact with this particular data type. Finally, it gives us a list of implemented protocols. These are additional modules that provide some sort of behavior that we expect that data type to adhere to if it implements a particular behavior. You can think of them as being similar in concept to interfaces in other programming languages.