Elixir Programming Language

Help commands

iex - Start Elixir’s Interactive Shell
h - Get Help info about function
i - Variable Data Type Information

Data Types

1. Integers

3, 777, -2, 0, 1_000_000

2. Floats

3.14, 0.00000001

3. Atoms
An atom is a constant whose name is its value. The booleans true and false are also the atoms :true and :false, respectively. Names of modules in Elixir are also atoms.

:name, :gender, :status

4. Strings

"Let it be"

iex(32)> "admin " <> "Max"
"admin Max"

--- Pattern matching ---

iex(34)> "check: " <> check_str = "check: 7"
"check: 7"

iex(35)> check_str
"7"

5. Lists List can contain mixed types of information

[1, 2]

--- List Concatenation ---

[1, 2] ++ [3, 4, 1]
[1, 2, 3, 4, 1]

--- List Subtraction ---

["foo", :bar, 42] -- [42, "bar"]
["foo", :bar]

[1,2,2,3,2,3] -- [1,2,3,2]
[2, 3]

[2] -- [2.0]
[2]

[2.0] -- [2.0]
[]

6. Tuples Tuples are similar to lists, but are stored contiguously in memory. This makes accessing their length fast but modification expensive; the new tuple must be copied entirely to memory.

{3.14, :pie, "Apple"}

--- PATTERN MATCHING ---

my_tuple = {:add, [1, 2]}
{:add, [1, 2]}

iex(43)> {atom, [first, second]} = my_tuple
{:add, [1, 2]}

iex(44)> atom
:add

iex(45)> first
1

7. Maps

newMap = %{:name => "Max", "hello" => :world}

iex(13)> newMap["hello"]
:world

Short syntax:

%{name: "Max", hello: :world}

{foo: "bar", hello: "world"}

--- PATTERN MATCHING ---

iex(38)> coder = %{"name" => "Max", "language" => "Elixir"}
%{"language" => "Elixir", "name" => "Max"}

iex(39)> %{"name" => name, "language" => language} = coder
%{"language" => "Elixir", "name" => "Max"}

iex(40)> name
"Max"

iex(41)> language
"Elixir"

8. Structs Structs are extensions built on top of maps that provide compile-time checks and default values.

iex> defmodule User do
...> defstruct name: "John", age: 27
...> end

iex> %User{}
%User{age: 27, name: "John"}
iex> %User{name: "Jane"}
%User{age: 27, name: "Jane"}

9. Conditional Expressions

 cond do
    age < 18 -> "You can't vote yet"
    age < 25 -> "You can vote"
    true -> "You can vote and can be a president also"
  end

10. Case Expressions

message = case Float.parse(age) do
  {age, _} when age < 18  -> "You are to young to vote"
  {age, _} when age < 25 -> "You are allowed to vote"
  {_age, _} -> "You can vote and can become the president yourself"
  :error -> "Invalid input"
end

11. Functions

Anonymous Functions

fn(age) ->
  case (Float.parse(age)) do
    {age, _} when age < 18  -> "You are not allowed to vote"
    {age, _} when age < 25 -> "You can vote"
    {_age, _} -> "You can vote and be a president also"
    :error -> "Invalid input"
  end
end

Named Functions

defmodule Voter do
  def check_age(age) do
    case Integer.parse(age) do
     {age, _} when age < 18  -> "You are not allowed yo vote yet"
     {age, _} when age < 25 -> "You can vote"
     {_age, _} -> "You can vote and even be a president"
     :error -> "Invalid input"
    end
  end
end