The Heart of the Algorithm - Introduction to APL Syntax and Problem Solving

Explore the fundamentals of APL programming in this 27-minute conference talk from APL Seeds '23. Learn about basic syntax, function order, reduction and outer product operators, and row/column sums. Follow along as Rich Park demonstrates how to solve a real-world problem: determining user attendance at online meetings based on join/leave times and session schedules. Discover how APL's concise notation allows for elegant solutions to complex problems, with a focus on comparing time intervals using outer products and the rank operator. Gain insights into the "heart of the algorithm" and how APL's approach maps thought processes directly to executable expressions.

Introduction
Functions and order of operations
Reduction operator
Outer product operator
Row and column sums
Problem: Who attended online user meetings?
Comparing session and attendance times
Use of outer product to compare all times
Use of rank operator to compare session durations
The Heart of the Algorithm
Questions