cgrothaus
3 different ways to build a list with conditional elements in Elixir (and what that has to do with application startup)
I wrote a blog post about 3 different ways to build a list with conditional elements in Elixir (and what that has to do with application startup).
Most Liked
Eiji
There are other ways to achieve such results for example using recursive functions.
defmodule Example do
def sample(list) do
List.foldr(list, [], fn
{false, _child_spec}, acc -> acc
{true, child_spec}, acc -> [child_spec | acc]
child_spec, acc -> [child_spec | acc]
end)
end
def sample2([]), do: []
def sample2([{false, _child_spec} | rest]), do: sample2(rest)
def sample2([{true, child_spec} | rest]), do: sample2([child_spec | rest])
def sample2([child_spec | rest]), do: [child_spec | sample2(rest)]
end
input = [:not_tuple, {false, :skip_me}, {true, :no_skip}]
Example.sample(input)
Example.sample2(input)
Helpful resources:
2
Popular Backend topics
There are 3 main formatters for Erlang which you can use from the command-line,
rebar3_format,
Steamroller
elmfmt.
Visual Studio Cod...
New
We all know how to teach recursion. We’ve done it for decades. We pick some honored, time-tested examples—Fibonacci numbers and factorial...
New
Such inflammatory, much wow. Unfortunately, Haskell itself agrees.
Some languages naturally lend themselves towards adoption. Some don’t...
New
So you’re enjoying using WebSockets with Elixir’s Phoenix Framework, and you want to send some binary messages. Maybe it’s an audio clip,...
New
Django 3.2 is just around the corner and it’s packed with new features. Django versions are usually not that exciting (it’s a good thing!...
New
Just a small test with lists in cython.
Considering echosystem, multithreading and ease of use, Julia is a clear winner here.
New
We take a deeper dive with Nathan Long into IOLists in Elixir. We cover what they are, how they work, the power they have when concatenat...
New
Erlang is famous for its introspecting powers. You can get a lot of information about the processes running in your nodes without any ext...
New
This was posted on the Elixir Forum and thought it was worth sharing here!
I love how the excitement of the author shines through and I ...
New
Ruby’s Struct is one of several powerful core classes which is often overlooked and under utilized compared to the more popular Hash clas...
New
Other popular topics
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
New
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...
New
Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...
New
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
New
The V Programming Language
Simple language for building maintainable programs
V is already mentioned couple of times in the forum, but I...
New
Create efficient, elegant software tests in pytest, Python's most powerful testing framework.
Brian Okken @brianokken
Edited by Kat...
New
Hi folks,
I don’t know if I saw this here but, here’s a new programming language, called Roc
Reminds me a bit of Elm and thus Haskell. ...
New
Node.js v22.14.0 has been released.
Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
Use advanced functional programming principles, practical Domain-Driven Design techniques, and production-ready Elixir code to build scal...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /revery
- /ubuntu
- /manjaro
- /spring
- /lua
- /diversity
- /julia
- /markdown
- /v








