Default arguments in Swift

Create a flexible API

Photo by Moon on Unsplash

Default arguments are great! This article explains what they are, and why they are fantastic. Go on, take a look!

Difficulty: Beginner | Easy | Normal | Challenging
This article has been developed using Xcode 11.5, and Swift 5.2.4

Prerequisites:

• For simplicity this article is written with the Swift Playground in mind.
• Some experience of functions is assumed

Functions

A simple example

Imagine that we have a function that prints a name and a message to the console. That function looks like the following:

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This gives us an opportunity: surely in almost every case we are going to to have the “Hello, World” message (ok, a stretch but bear with me) — so we want “Hello, World” to be the default of the function. Is this possible? It turns out that yes, yes it is.

Creating a default parameter

The best thing about this default parameter is that it won’t change any existing calls to…