Elixir Cheat Sheet

Elixir syntax, pattern matching, pipe operators, and OTP concurrency primitives for building fault-tolerant BEAM applications.

2 PagesAdvancedMar 30, 2026

Basic Syntax

Bindings, control flow, and printing.

elixir

age = 30name = "Ada"pi = 3.14159if age >= 18 do  IO.puts("#{name} is an adult")endfor i <- 0..4 do  IO.puts("Count: #{i}")end

Pattern Matching & Pipe Operator

Destructuring and composing transformations.

elixir

{status, message} = {:ok, "loaded"}   # destructuring match[first | rest] = [1, 2, 3, 4]          # head/tail matchIO.inspect(first)                      # 1IO.inspect(rest)                       # [2, 3, 4]nums = [5, 3, 1, 4, 2]result =  nums  |> Enum.filter(&(&1 > 2))  |> Enum.map(&(&1 * 2))  |> Enum.sum()                        # pipe: nums |> filter |> map |> sum

Processes & OTP

GenServer and lightweight process concurrency.

elixir

defmodule Counter do  use GenServer  def start_link(initial), do: GenServer.start_link(__MODULE__, initial)  def init(state), do: {:ok, state}  def handle_call(:get, _from, state), do: {:reply, state, state}  def handle_call(:increment, _from, state), do: {:reply, state + 1, state + 1}end{:ok, pid} = Counter.start_link(0)GenServer.call(pid, :increment)GenServer.call(pid, :get)   # 1

Core Keywords & Operators

Common Elixir language constructs.

|>- pipe operator, passes left result as first arg to right function
def / defp- public and private module function definitions
case / cond- multi-branch pattern matching / condition dispatch
%{}- map literal, e.g. %{name: "Ada"}
GenServer- OTP behaviour for stateful server processes
spawn / send / receive- lightweight process creation and message passing
Enum / Stream- eager and lazy collection-processing modules

Pro Tip

Let it crash: rely on OTP supervisors to restart failing processes instead of wrapping every operation in defensive try/rescue — Elixir's fault tolerance is designed around supervision trees.

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