Data Types

Atom

:error

{:error, reason} = {:error, "file not found"}
reason

{:ok, msg} = {:ok, "status 200 ok"}
msg

String & Code Points

# Strings are UTF-8 encoded
name = "Octallium"
name

is_binary(name)

msg = "Hello " <> name

"Hello " <> name = msg
name

<> = name
head

head == ?O

# Pattern Matching
<<"O", rest::binary>> = name
rest

<<"Oc", rest::binary>> = name
rest

# Specify Size
<> = name
head

# Char list
chars = 'Octallium'
chars

'hello ' ++ chars

is_list(chars)

# Codepoints
?a

Processes

my_pid = self()
my_pid

is_pid(my_pid)

Lists Are Not Lists - They are Linked List!!!

list = ["a", "b", "c"]

list[0]

Enum.at(list, 1)

[first, second, third] = list

second

[_, _, third] = ["a", "b", "c"]
third

hd(list)

tl(list)

[h | t] = list
h

t

Tuple

{a, b} = {1, 2}

{:reply, msg, state} = {:reply, "Octallium found!", ["Octallium", "Louis", "Chiko"]}
msg

Keyword List

data = [a: 1, b: 2, c: 3]

[{:a, 1}] == [a: 1]

data[:c]

Maps

my_map = %{a: 1, b: 2, c: 3}
my_map

%{a: first, b: second, c: third} = %{a: 1, b: 2, c: 3}
first

%{b: second} = my_map
second

my_map.a

map2 = %{"a" => 1, "b" => 2, "c" => 3}

%{"c" => c} = map2
c

map2 = %{map2 | "c" => 4}

my_map = %{my_map | a: 5}

Struct

defmodule User do
  defstruct username: "", age: nil, email: ""
end

user1 = %User{username: "Octallium", age: 14, email: "octobot@sample.com"}

%{username: username} = user1
username

user1 = %{user1 | age: 21}
user1