By the end of this section, you’ll know:

  • Gain an understanding of basic Elixir Types


Although Elixir is not a statically typed language, it does have the concept of types. The basic types we’ll work with are:

  • Numbers
  • Floats
  • Booleans
  • Strings
  • Atoms
  • Lists
  • Tuples

We’ll use all of these types throughout this course (and you’ll use them throughout your Elixir career), so let’s look at how to create/use each one.


A number type comprises the Integer and the Float types. Just like how it sounds, the number types are plain ole’ numbers.


Open up your terminal window and type iex to open your interactive elixir shell.

Next type the following expression into the shell and them press enter:

1 + 1

You should see output like this:

iex(5)> 1 + 1

Basic math operations like the one above work as you would expect them to (Subtraction, Multiplication etc.)

We can check if a value is an integer by using the function is_integer/1. Try it! Type is_integer(42) into IEx, and press enter. You should see something like the following:

iex> is_integer(42)

Now let’s try a number with a decimal point. Type is_integer(3.14) into IEx, and press enter. The result should be like this:

iex> is_integer(3.14)

Why is this false? Because 3.14 is not in integer, it’s a Float. Let’s take a look at floats.

Docs for Integer


Creating/using floats is the same as creating integers, typed as you might expect: They require a dot followed by at least one digit. Try typing the following floats in IEX:

iex> 1.0
iex> 2000.8
iex> 1.0e-10

We can check if a value is a float by using the is_float/1 function. Type the following into iex:

iex> is_float(3.14)

Let’s see what other mathematical operations we can practice.

Try typing some of the operations listed bellow into your iex console.

iex> 1 + 1        # 2
iex> div(10, 2)   # 5
iex> rem(10, 3)   # 1
iex> ## Or without parenthesis
iex> rem 10, 3    # 1
iex> 10 / 2

As you can see operations we are familiar with like div/2 behave as we expect

iex> div(9, 3)

What about operators that look less familiar?

The rem operator will return the remainder of a division operations

iex> rem(10, 3)

Try some other commands out to see what else you can do.

Float docs

Hex, Octal, Binary

Elixir supports notations for entering binary, hex, octal, and hexadecimal numbers


But let’s not worry about these for now.


Booleans are true and false types. We can use these types to check truth conditions.

Type the following lines(one at a time) into the iex console:

iex> true ## true
iex> true == false

It’s possible to check if a variable is a boolean by using the is_boolean/1 function:

Try typing the following into the console:

iex> a = 1
iex> is_boolean(true) # true
iex> is_boolean(a) # false
iex> false
iex> true

Elixir also provides or, and, not as boolean operators. These operators are strict in that they expect a boolean as an argument.

Type the following into the console:

42 && true
nil || 42


Strings in Elixir are values between double quotes (") and are UTF-8 encoded. Try typing the following one line at a time into the console (feel free to copy and paste the last one):

iex> "Hello"
iex> "World"
iex> "❤️💛💚💙"

We can output values to the console using the IO.puts/1 command. Let’s try and output our string to the console. Type the following:

iex> IO.puts("hello world!")
hello world!

It prints the string to stdout by default, and then returns the :ok tuple, to indicate that there were no errors.

Just like integers, the String module has a lot of functions built-in to the standard library we can use out of the box.

Type the following lines onto the console one at a time:

iex> String.length("hello world") # 11
iex> String.upcase("hello world") # HELLO WORLD

String Interpolation

type the following into the console

receiver = "World"
"Hello #{receiver}"

Variables are interpolated using the #{variable}

More documentation on the String module is available at https://hexdocs.pm/elixir/String.html.

Concatenate Operator

So what happens when we want to put two separate strings together?

We use the concatenate operator.

It looks like this: <>

Now try using it. Type the following into the console:

iex> "Hello" <> "World" # "HelloWorld"


We’ll use atoms a lot in Elixir. They are their own constant values. If you’re familiar with Ruby, these are symbols or enumerations in C/C++.

For instance, these are all atoms:

iex> :hello
iex> :world
iex> :true
iex> :this_has_underscores