Learning resources

"I have long been struck by the contrast between the success with which the adventurous learn APL by simply using it, and the frequent failure of lecture courses to communicate the simplicity and applicability of the language." Ken Iverson. A Working Introduction to APL, 1981.

To facilitate self-study, the resources here are classified by target audience. However, if you get stuck, don't hesitate to request help in one of the many chat rooms and forums or ask a question on Stack Exchange.

It may be beneficial to learn the APL terminology.

For non-programmers

Some of the best resources for somebody new to APL and programming in general are:

Interactive

• The Learn tab on TryAPL
• The Zark APL Tutor
• The APL Challenge

Books

• Mastering Dyalog APL by Bernard Legrand
• APL2 at a Glance by Jim Brown, Sandra Pakin, and Ray Polivka (also in German)
• Learning APL with APLX (also as PDF)
• MENACE in APL (early reinforcement learning project)
• A Practical Introduction to APL 1 & 2 (3 & 4 is for experts)

Text

• APL Wiki's simple examples
• APL a Day: Introduction, Functions, Arrays, Values, Arrays have Shape
• The tutorial from the old APL Wiki

Video series

• APL Quest 2016 by Adám Brudzewsky
• Découvrez le langage APL: parts 1, 2, 3 by Eric Schrafstetter (in French)
• Learn APL with neural networks
• APLtrainer tutorials

Follow one or a couple of these tutorials through and play around a bit. To learn APL the advice is similar to that for learning other languages: have a goal (something you want to accomplish) and try to do it. Along the way you are sure to come across the pitfalls and gotchas of the language, and with time you may come to understand what APL thinking means.

For programmers unfamiliar with APL

This is a list of tutorials and other resources of interest to someone who knows about programming or is familiar with another programming language, but wants to learn more about APL. See also APL Wiki's lists of advanced examples, books, and papers. "Trying APL" has examples for all primitives.

Interactive

• TryAPL online interpreter with lessons
• Zark tutorial
• APL deserves its renaissance too (on John Scholes' Conway's Game of Life)
• The APL Challenge

Text courses

• APL Course (Dyalog)
• Learn X in Y minutes
• Let’s Learn A Programming Language, part 1, part 2, and FizzBuzz
• Artificial Neural Networks

Video

• Learn APL with neural networks (series)
• An Introduction to APL
• fast.ai APL Study Group (series) by Jeremy Howard

Books

• Mastering Dyalog APL by Bernard Legrand
• Learning APL by Stefan Kruger
• Getting started in APL by solving Project Euler problems 1 to 50 by Matthias Geiss
• APL2 at a Glance by Jim Brown, Sandra Pakin, Ray Polivka (also in German)

For novice APLers

Besides for APL Wiki's advanced examples, you can hone your APL skill with these materials.

Books

• APL Cultivations by Adám Brudzewsky (edited by Stefan Kruger)
• APL2 in Depth by Norman Thomson and Ray Polivka
• A Practical Introduction to APL 3 & 4

Videos

• Learn APL with neural networks (series)
• Triplets pythagoriciens by OsKaR: A mathematical problem used as an introduction to the expressive power of APL (French series)
• Data Science Puzzle in APL by yernab: analysis of scenarios from Dungeons & Dragons

Exercises

• Code golf: Competition in which participants strive to achieve the shortest possible source code
• Kattis: Very large collection of problems with automated checking of APL solutions
• APL Monday: Small APL reading exercises by Dyalog Ltd posted on X/Twitter, Mastodon, BlueSky, LinkedIn, Instagram, and Facebook
• APL Exercises by Roger Hui
• APLcart Quiz: Be challenged to write a function for a given task or to explain what a given function does (based on APLcart data)
• APL Crosswords: 1 4 5 — Fill in expressions and snippets to fulfil all the clues
• 2016 Year Game: Find APL expressions involving exactly the digits 2 0 1 6 in that order to equal the numbers 0 to 100
• 2017 Code Golf Challenge: Find the shortest possible APL expression that evaluates 1…52 without using any number or character literals
• APL Quest: Website with automatic validation of solutions to problems from Phase 1 of past APL Problem Solving Competitions (see APL Quest)
• Advent of Code: Advent calendar of small programming puzzles, popular with APL programmers
• APL-eusis: A game for honing your ability to "think in APL"

For advanced APLers

Here is a list of "how-to"s on various subjects:

• Learn APL with neural networks (video series)
• Error trapping with Dyalog APL
• Error trapping in Dyalog APL forms
• Cryptography with .Net
• WPF XAML demo

Haven't used APL in a while?

Those who learned APL "in the early days" should note that several implementations have made significant extensions to the language and system in the last decade or two.

General

• Dyalog APL for other APL users (video)
• Assignment
• Control structures
• Namespaces
• Migration level
• User-defined operators
• Error trapping
• Shyness
• Namelists
• Keywords
• Object-oriented programming
• Total array ordering
• Leading axis theory
• Complex numbers

New primitive functions

• GCD and LCM
• Same (⊢ and ⊣)
• Materialise and Index (⌷)
• Depth and Match (≡)
• Tally and Not Match (≢)
• Nub Sieve (≠)
• Where and Interval Index (⍸)
• Nest and Partition (⊆)

New primitive operators

• Power operator
• Commute and Constant (⍨)
• At (@)
• Bind and Beside (∘)
• Atop and Rank (⍤)
• Over (⍥)
• Key (⌸)
• Stencil (⌺)
• Variant (⍠)
• Spawn (&)

Lambdas (dfns)

• Intro
• Details
• Operators
• The dfns workspace (collection of categorized utilities with extensive comments and notes)

Tacit programming

• Intro
• Details
• Short video
• Long video
• APL Cultivation lesson
• Function composition