Getting Started with Elixir

In this post we will learn a little bit about Elixir basic types, strings, atoms, integers, float, booleans, lists and tuples. I will be using Elixir 1.0.2 . To install Elixir you can access the installation guide on Elixir documentation, http://elixir-lang.org/install.html.

We will be starting by using the REPL console that comes bundled with Elixir. So lets get started.

Strings

Strings in Elixir are inserted between double quotes:

iex> "Hello World"
"Hello World"

We can use multi-line strings:

iex> """
I'm a multi-line
string
"""

Atoms

Atoms are just like symbols in Ruby. They consist of a colon, followed by letters, digits, and underscores.

:foo
:bar
:hello@world
:”Hello Elixir World”
:this_is_a_short_sentence

In Elixir, atoms are used frequently to tag response types.

Numbers

Integers

Integers can be written in various ways, let’s see that:

9876789
1_000_000
2_123 == 2123 #Like in Ruby we can use underscores to make numbers easier to read

Float Points

Floating point numbers have a decimal point.

1.78
0.56

Booleans

In Elixir, everything, excepting “false” and “nil” it’s true. “false” and “nil” are both alias to the atoms with the same name, :false and :nil.

iex>:false == false
true

iex>nil == :nil
true

Lists

Lists are stored in memory as linked lists, meaning that each element in a list holds its value and points to the following element until the end of the list is reached.

[1,2,3]

[:foo, :bar]

[:bar, 1, [2,3,4], :foo]

Two lists can be concatenated and subtracted with ++/2 and –/2 operators.

iex> [1,2,3] ++ [4,5,6]
[1, 2, 3, 4, 5, 6]

iex> [1, true, 2, false, 3, true] **--** [true, false]
[1, 2, 3, true]

We can access the head and the tail of a list as follows:

iex> [head | tail ] = [1, 2]
iex> head
1
iex> tail
2

Note:

Functions in Elixir are identified by name and by number of arguments (i.e. arity). Therefore, is_boolean/1 identifies a function named is_boolean that takes 1 argument.is_boolean/2 identifies a different (nonexistent) function with the same name but different arity. — *http://elixir-lang.org/

Tuples

Tuples, on the other hand, are stored contiguously in memory.

iex> {1, 2, 3}
{1, 2, 3}

iex> {:ok, "hello"}
{:ok, "hello"}

We can access a Tuple element with:

iex> elem({:ok, "Hello"}, 1)
"Hello"

And the tuple size with:

iex> tuple_size({:ok, "Hello"})
2

Note:

Tuples are used very frequently in Pattern Matching and in return values from various functions. In the next posts we will talk a little more about it