【Swift 60秒】40 - Parameter labels

0x00 Lesson

We wrote our square() function like this:

func square(number: Int) -> Int {
	return number * number
}
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That names its parameter number, so we can use number inside the function to refer to it, but we must also use the name when running the function, like this:

let result = square(number: 8)
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Swift lets us provide two names for each parameter: one to be used externally when calling the function, and one to be used internally inside the function. This is as simple as writing two names, separated by a space.

To demonstrate this, here’s a function that uses two names for its string parameter:

func sayHello(to name: String) {
	print("Hello, \ (name)!")
}
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The parameter is called to name, which means externally it’s called to, but internally it’s called name. This gives variables a sensible name inside the function, but means calling the function reads naturally:

sayHello(to: "Taylor")
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