Learn Elixir - 9 Code Examples & CST Typing Practice Test

Elixir is a functional, concurrent, fault-tolerant programming language built on the Erlang VM (BEAM). It enables highly scalable, distributed, and resilient applications - ideal for real-time systems, telecom-grade reliability, and web applications via Phoenix.

View all 9 Elixir code examples →

Elixir Counter and Theme Toggle Elixir Simple Calculator Elixir FizzBuzz Elixir Factorial Elixir Fibonacci Elixir List Comprehension Elixir Map Filtering Elixir Anonymous Functions with Capture Elixir Reduce Example

Learn ELIXIR with Real Code Examples

Updated Nov 18, 2025

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Code Sample Descriptions

Elixir Counter and Theme Toggle

defmodule Counter do
    def run do
        count = 0
        is_dark = false

        update_ui = fn ->
        IO.puts("Counter: #{count}")
        IO.puts("Theme: #{if is_dark, do: \"Dark\", else: \"Light\"}")
        end

        increment = fn ->
        count = count + 1
        update_ui.()
        end

        decrement = fn ->
        count = count - 1
        update_ui.()
        end

        reset = fn ->
        count = 0
        update_ui.()
        end

        toggle_theme = fn ->
        is_dark = !is_dark
        update_ui.()
        end

        # Simulate actions
        update_ui.()
        increment.()
        increment.()
        toggle_theme.()
        decrement.()
        reset.()
    end
end

Counter.run()

Demonstrates a simple counter with theme toggling using Elixir variables and console output.

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Elixir Simple Calculator

add = fn a, b -> a + b end
subtract = fn a, b -> a - b end
multiply = fn a, b -> a * b end
divide = fn a, b -> a / b end

IO.puts("Add 5 + 3: #{add.(5,3)}")
IO.puts("Subtract 5 - 3: #{subtract.(5,3)}")
IO.puts("Multiply 5 * 3: #{multiply.(5,3)}")
IO.puts("Divide 6 / 2: #{divide.(6,2)}")

Demonstrates addition, subtraction, multiplication, and division with anonymous functions.

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Elixir FizzBuzz

Enum.each(1..15, fn n ->
    IO.puts cond do
        nrem(n, 15) == 0 -> "FizzBuzz"
        nrem(n, 3) == 0 -> "Fizz"
        nrem(n, 5) == 0 -> "Buzz"
        true -> Integer.to_string(n)
    end
end)

Classic FizzBuzz problem using pattern matching and anonymous functions.

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Elixir Factorial

factorial = fn
    0 -> 1
    n -> n * factorial.(n - 1)
end

IO.puts("Factorial of 5: #{factorial.(5)}")

Recursive factorial function in Elixir.

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Elixir Fibonacci

fibonacci = fn
    0 -> 0
    1 -> 1
    n -> fibonacci.(n-1) + fibonacci.(n-2)
end

Enum.each(0..9, fn n -> IO.puts(fibonacci.(n)) end)

Recursive Fibonacci sequence generator.

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Elixir List Comprehension

numbers = 1..10
squares = for n <- numbers, rem(n, 2) == 0, do: n * n
IO.inspect(squares)

Using list comprehension to square even numbers.

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Elixir Map Filtering

scores = %{alice: 10, bob: 5, charlie: 12}
high_scores = for {k, v} <- scores, v >= 10, into: %{}, do: {k, v}
IO.inspect(high_scores)

Filtering a map based on value conditions.

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Elixir Anonymous Functions with Capture

add = &(&1 + &2)
IO.puts(add.(3, 7))

Using the capture operator to shorten anonymous functions.

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Elixir Reduce Example

numbers = [1,2,3,4,5]
sum = Enum.reduce(numbers, 0, fn x, acc -> x + acc end)
IO.puts(sum)

Summing a list of numbers using Enum.reduce.

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Frequently Asked Questions about Elixir

What is Elixir?

What are the primary use cases for Elixir?

Highly concurrent real-time systems. Scalable web backends (Phoenix). Distributed and fault-tolerant applications. Event-driven architectures. Messaging systems. Telecom-level resilience workloads. IoT and device message brokers

What are the strengths of Elixir?

Massively scalable. Extremely fault tolerant. Low-latency real-time features. Easy concurrency model. Rock-solid reliability from BEAM

What are the limitations of Elixir?

Smaller ecosystem compared to Python/JS. Learning curve for FP + OTP. Not ideal for heavy numerical computing. Limited mobile/desktop tooling. Requires BEAM mental model

How can I practice Elixir typing speed?

CodeSpeedTest offers 9+ real Elixir code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Elixir Counter and Theme Toggle

defmodule Counter do
    def run do
        count = 0
        is_dark = false

        update_ui = fn ->
        IO.puts("Counter: #{count}")
        IO.puts("Theme: #{if is_dark, do: \"Dark\", else: \"Light\"}")
        end

        increment = fn ->
        count = count + 1
        update_ui.()
        end

        decrement = fn ->
        count = count - 1
        update_ui.()
        end

        reset = fn ->
        count = 0
        update_ui.()
        end

        toggle_theme = fn ->
        is_dark = !is_dark
        update_ui.()
        end

        # Simulate actions
        update_ui.()
        increment.()
        increment.()
        toggle_theme.()
        decrement.()
        reset.()
    end
end

Counter.run()

Demonstrates a simple counter with theme toggling using Elixir variables and console output.

Let’s Try →

Elixir Simple Calculator

add = fn a, b -> a + b end
subtract = fn a, b -> a - b end
multiply = fn a, b -> a * b end
divide = fn a, b -> a / b end

IO.puts("Add 5 + 3: #{add.(5,3)}")
IO.puts("Subtract 5 - 3: #{subtract.(5,3)}")
IO.puts("Multiply 5 * 3: #{multiply.(5,3)}")
IO.puts("Divide 6 / 2: #{divide.(6,2)}")

Demonstrates addition, subtraction, multiplication, and division with anonymous functions.

Let’s Try →

Elixir FizzBuzz

Enum.each(1..15, fn n ->
    IO.puts cond do
        nrem(n, 15) == 0 -> "FizzBuzz"
        nrem(n, 3) == 0 -> "Fizz"
        nrem(n, 5) == 0 -> "Buzz"
        true -> Integer.to_string(n)
    end
end)

Classic FizzBuzz problem using pattern matching and anonymous functions.

Let’s Try →

Elixir Factorial

factorial = fn
    0 -> 1
    n -> n * factorial.(n - 1)
end

IO.puts("Factorial of 5: #{factorial.(5)}")

Recursive factorial function in Elixir.

Let’s Try →

Elixir Fibonacci

fibonacci = fn
    0 -> 0
    1 -> 1
    n -> fibonacci.(n-1) + fibonacci.(n-2)
end

Enum.each(0..9, fn n -> IO.puts(fibonacci.(n)) end)

Recursive Fibonacci sequence generator.

Let’s Try →

Elixir List Comprehension

numbers = 1..10
squares = for n <- numbers, rem(n, 2) == 0, do: n * n
IO.inspect(squares)

Using list comprehension to square even numbers.

Let’s Try →

Elixir Map Filtering

scores = %{alice: 10, bob: 5, charlie: 12}
high_scores = for {k, v} <- scores, v >= 10, into: %{}, do: {k, v}
IO.inspect(high_scores)

Filtering a map based on value conditions.

Let’s Try →

Elixir Anonymous Functions with Capture

add = &(&1 + &2)
IO.puts(add.(3, 7))

Using the capture operator to shorten anonymous functions.

Let’s Try →

Elixir Reduce Example

numbers = [1,2,3,4,5]
sum = Enum.reduce(numbers, 0, fn x, acc -> x + acc end)
IO.puts(sum)

Summing a list of numbers using Enum.reduce.

Let’s Try →

Frequently Asked Questions about Elixir

What is Elixir?

What are the primary use cases for Elixir?

What are the strengths of Elixir?

Massively scalable. Extremely fault tolerant. Low-latency real-time features. Easy concurrency model. Rock-solid reliability from BEAM

What are the limitations of Elixir?

Smaller ecosystem compared to Python/JS. Learning curve for FP + OTP. Not ideal for heavy numerical computing. Limited mobile/desktop tooling. Requires BEAM mental model

How can I practice Elixir typing speed?

CodeSpeedTest offers 9+ real Elixir code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.