teaching machines

CS 347: Lecture 15 – Higher-order Functions

October 13, 2020 by Chris Johnson. Filed under fall-2020, lectures, webdev.

Dear students:

In this lecture, we hit up higher-order functions, a feature of modern languages that will shorten up your code considerably. Once you know a few of these higher-order functions, you may never write loops again. Why? Because so many of our looping algorithms follow certain patterns, we can generalize those patterns into reusable functions—leaving holes in them for the parts of algorithms that change. Those holes are formalized as parameters, which we fill by passing functions that produce the one-off behaviors.

We’ll be using these higher-order functions frequently when we build React apps.

Here’s your TODO list:

• Watch Map, in which we discuss a pattern for turning one array into another array by transforming each element.
• Watch Filter, in which we discuss a pattern for selecting out elements from an array that meet some criteria.
• Watch Reduce, in which we discuss a very general pattern for accumulating elements of an array into some other structure.
• Finish project 1. Be sure to check your work against the enumeration of project 1 requirements.
• There will be no peer review on Thursday.

See you next time.

Sincerely,