Int.times()

Sat, 27 Aug 2022 00:00:00 +0000

When writing yesterday’s post about iterating through a range or collection and using the underscore to throw away the item, I had in the back of my mind that there should be a more straightforward way of doing something a number of times.

Just to re-iterate (lol), here’s the issue. If we want to print “Here’s the thing” three times, in Swift the simplest we can do is:

for _ in 1…3 { print(“Here’s the thing”) }

I had the idea, that this should really be a method of the Int type. And in fact I could write it as an extension that took a closure. Then we could just do this:

3.times { print(“Here’s the thing”) }

That feels much more like the Swift way of doing things (although I probably picked it up during a brief flirtation with Ruby). Of course, I’d implement it with a while loop and a counter, so there’d still be the counter memory allocated, but only for an Int rather than the Array element type.

With this system, the problem I was talking about yesterday:

let thingStrings = [“Thing one”, “Thing two”, “Thing three”]

for _ in thingStrings { print(“Here’s the thing”) }

would become:

let thingStrings = [“Thing one”, “Thing two”, “Thing three”]

thingStrings.count.times { print(“Here’s the thing”) }

Which is, I admit, not amazingly better, but better, especially if the compiler is allocating the memory and filling it with each array value in the first example (which I don’t know if it is, but am increasingly interested in finding out).

Feeling pretty pleased with myself for inventing this new Int method, I had a extra thought that in fact, the Swift community may already of invented this and incorporated it in the language, so I should google it first. It turns out it’s not aprt of the official language, but neither (unsurprisingly) am I the first to think of it.

There’s a Stack Overflow answer to a question “What is the shortest way to run same code n times in Swift?”

So shout out to Matteo Piombo for doing the work for my idea seven years before I had it! It’s still just for code clarity, but great use of extensions and closures.

I still maintain that for _ in is not great, and that for each in where each was a synonym for the underscore would be the prettiest solution. A likely con of this proposal is that is would be a code breaking change for any code that has already uses for each which could be quite common.

Stack-Overflow on blog.iankulin.com

Int.times()