Part 0 · 1 chapters · ~8 min

Basics

Installing Elixir with mise or asdf, iex, basic types (integers, floats, atoms, strings, lists, tuples, maps), immutability, the match operator, modules and named functions, multi-clause functions and guards, anonymous functions, the pipe operator, Enum and Stream, and mix new.

First code

code

defmodule Fees do
  # multiple clauses chosen by pattern and guard
  def fee(_amount, :ussd), do: 2_000
  def fee(amount, :app) when amount <= 500_000, do: 1_000
  def fee(amount, :app) when amount <= 5_000_000, do: 2_500
  def fee(_amount, :app), do: 5_000
end

transfers
|> Enum.filter(&(&1.status == :completed))
|> Enum.map(&(&1.amount_kobo + Fees.fee(&1.amount_kobo, &1.channel)))
|> Enum.sum()

{:ok, account} = Accounts.fetch("acc_1")     # raises MatchError if it returns {:error, _}
# iex> elixir --version → Elixir 1.19.5 (compiled with Erlang/OTP 28); running on OTP 29 here

ELIXIR IN SIX IDEAS

what is different from JavaScript or Python

swipe the figure sideways, or tap expand for full screen

1/4

immutability

Data is immutable: Map.put returns a new map. There is no shared mutable state to race on.

no mutationno data races