Swift Programming Tutorial: allSatisfy

Understand How to Use allSatisfy in Just a Few Minutes

Photo by Tanja Tepavac on Unsplash

I admit that allSatisfy is one of those very useful functions I learned late in my Swift coding journey. I discovered it years ago when my boss/mentor at a previous company reviewed my code and pointed out some lines that could be refactored to improve readability and efficiency using allSatisfy.

This article is part of my Swift Programming Tutorial series.

So what’s allSatisfy anyway? Imagine you’re the captain of a starship, soaring through the galaxy of Swift collections. Your mission? To ensure your crew (aka, the elements in your array) all meet a specific condition before you boldly go where no programmer has gone before. But you don’t have time to interrogate each crew member manually — what kind of captain does? You need an efficient tool, one that can check every member of your squad with a single command. Enter allSatisfy, your first officer of validation.

Without allSatisfy – The Tiring Manual Way

Let’s say we want to check if all numbers in an array are even. Without allSatisfy, you'd need a loop to manually inspect each number and track the result.

let numbers = [2, 4, 6, 8]
var allEven = true

for number in numbers {…